Menu on one page is bolder

how did you embed the Montserrat Font?
on your Enfold – @font-face rules of the other pages (not team page) i can only find Montserrat Thin Regular. (400) and no 800 style. So your font-weight set to 800 is only browser rendering.

Next : that team page loads 15 rules @font-face – if i switch off that css in the dev tools – the Team will be normal as the other items.
Where does that come from? Are these loaded by that feed? Maybe it is possible to instruct that feed ( is it a plugin? ) to use the theme fonts. Then we can load a better prepared Montserrat Font.

! As far as i know – you can choose on generating the template for that feed use as font: “Standard”- and that means it uses the theme fonts.

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/* cyrillic-ext */
@font-face {
  font-family: 'Montserrat';
  font-style: italic;
  font-weight: 400;
  src: url(https://fonts.gstatic.com/s/montserrat/v26/JTUFjIg1_i6t8kCHKm459Wx7xQYXK0vOoz6jq6R9WXV0oJC8MLnbtrVK.woff) format('woff');
  unicode-range: U+0460-052F, U+1C80-1C8A, U+20B4, U+2DE0-2DFF, U+A640-A69F, U+FE2E-FE2F;
}
/* cyrillic */
@font-face {
  font-family: 'Montserrat';
  font-style: italic;
  font-weight: 400;
  src: url(https://fonts.gstatic.com/s/montserrat/v26/JTUFjIg1_i6t8kCHKm459Wx7xQYXK0vOoz6jq6R9WXx0oJC8MLnbtrVK.woff) format('woff');
  unicode-range: U+0301, U+0400-045F, U+0490-0491, U+04B0-04B1, U+2116;
}
/* vietnamese */
@font-face {
  font-family: 'Montserrat';
  font-style: italic;
  font-weight: 400;
  src: url(https://fonts.gstatic.com/s/montserrat/v26/JTUFjIg1_i6t8kCHKm459Wx7xQYXK0vOoz6jq6R9WXd0oJC8MLnbtrVK.woff) format('woff');
  unicode-range: U+0102-0103, U+0110-0111, U+0128-0129, U+0168-0169, U+01A0-01A1, U+01AF-01B0, U+0300-0301, U+0303-0304, U+0308-0309, U+0323, U+0329, U+1EA0-1EF9, U+20AB;
}
/* latin-ext */
@font-face {
  font-family: 'Montserrat';
  font-style: italic;
  font-weight: 400;
  src: url(https://fonts.gstatic.com/s/montserrat/v26/JTUFjIg1_i6t8kCHKm459Wx7xQYXK0vOoz6jq6R9WXZ0oJC8MLnbtrVK.woff) format('woff');
  unicode-range: U+0100-02BA, U+02BD-02C5, U+02C7-02CC, U+02CE-02D7, U+02DD-02FF, U+0304, U+0308, U+0329, U+1D00-1DBF, U+1E00-1E9F, U+1EF2-1EFF, U+2020, U+20A0-20AB, U+20AD-20C0, U+2113, U+2C60-2C7F, U+A720-A7FF;
}
/* latin */
@font-face {
  font-family: 'Montserrat';
  font-style: italic;
  font-weight: 400;
  src: url(https://fonts.gstatic.com/s/montserrat/v26/JTUFjIg1_i6t8kCHKm459Wx7xQYXK0vOoz6jq6R9WXh0oJC8MLnbtg.woff) format('woff');
  unicode-range: U+0000-00FF, U+0131, U+0152-0153, U+02BB-02BC, U+02C6, U+02DA, U+02DC, U+0304, U+0308, U+0329, U+2000-206F, U+20AC, U+2122, U+2191, U+2193, U+2212, U+2215, U+FEFF, U+FFFD;
}
/* cyrillic-ext */
@font-face {
  font-family: 'Montserrat';
  font-style: normal;
  font-weight: 400;
  src: url(https://fonts.gstatic.com/s/montserrat/v26/JTUSjIg1_i6t8kCHKm459WRhyyTh89ZNpQ.woff2) format('woff2');
  unicode-range: U+0460-052F, U+1C80-1C8A, U+20B4, U+2DE0-2DFF, U+A640-A69F, U+FE2E-FE2F;
}
/* cyrillic */
@font-face {
  font-family: 'Montserrat';
  font-style: normal;
  font-weight: 400;
  src: url(https://fonts.gstatic.com/s/montserrat/v26/JTUSjIg1_i6t8kCHKm459W1hyyTh89ZNpQ.woff2) format('woff2');
  unicode-range: U+0301, U+0400-045F, U+0490-0491, U+04B0-04B1, U+2116;
}
/* vietnamese */
@font-face {
  font-family: 'Montserrat';
  font-style: normal;
  font-weight: 400;
  src: url(https://fonts.gstatic.com/s/montserrat/v26/JTUSjIg1_i6t8kCHKm459WZhyyTh89ZNpQ.woff2) format('woff2');
  unicode-range: U+0102-0103, U+0110-0111, U+0128-0129, U+0168-0169, U+01A0-01A1, U+01AF-01B0, U+0300-0301, U+0303-0304, U+0308-0309, U+0323, U+0329, U+1EA0-1EF9, U+20AB;
}
/* latin-ext */
@font-face {
  font-family: 'Montserrat';
  font-style: normal;
  font-weight: 400;
  src: url(https://fonts.gstatic.com/s/montserrat/v26/JTUSjIg1_i6t8kCHKm459WdhyyTh89ZNpQ.woff2) format('woff2');
  unicode-range: U+0100-02BA, U+02BD-02C5, U+02C7-02CC, U+02CE-02D7, U+02DD-02FF, U+0304, U+0308, U+0329, U+1D00-1DBF, U+1E00-1E9F, U+1EF2-1EFF, U+2020, U+20A0-20AB, U+20AD-20C0, U+2113, U+2C60-2C7F, U+A720-A7FF;
}
/* latin */
@font-face {
  font-family: 'Montserrat';
  font-style: normal;
  font-weight: 400;
  src: url(https://fonts.gstatic.com/s/montserrat/v26/JTUSjIg1_i6t8kCHKm459WlhyyTh89Y.woff2) format('woff2');
  unicode-range: U+0000-00FF, U+0131, U+0152-0153, U+02BB-02BC, U+02C6, U+02DA, U+02DC, U+0304, U+0308, U+0329, U+2000-206F, U+20AC, U+2122, U+2191, U+2193, U+2212, U+2215, U+FEFF, U+FFFD;
}
/* cyrillic-ext */
@font-face {
  font-family: 'Montserrat';
  font-style: normal;
  font-weight: 700;
  src: url(https://fonts.gstatic.com/s/montserrat/v26/JTUSjIg1_i6t8kCHKm459WRhyyTh89ZNpQ.woff2) format('woff2');
  unicode-range: U+0460-052F, U+1C80-1C8A, U+20B4, U+2DE0-2DFF, U+A640-A69F, U+FE2E-FE2F;
}
/* cyrillic */
@font-face {
  font-family: 'Montserrat';
  font-style: normal;
  font-weight: 700;
  src: url(https://fonts.gstatic.com/s/montserrat/v26/JTUSjIg1_i6t8kCHKm459W1hyyTh89ZNpQ.woff2) format('woff2');
  unicode-range: U+0301, U+0400-045F, U+0490-0491, U+04B0-04B1, U+2116;
}
/* vietnamese */
@font-face {
  font-family: 'Montserrat';
  font-style: normal;
  font-weight: 700;
  src: url(https://fonts.gstatic.com/s/montserrat/v26/JTUSjIg1_i6t8kCHKm459WZhyyTh89ZNpQ.woff2) format('woff2');
  unicode-range: U+0102-0103, U+0110-0111, U+0128-0129, U+0168-0169, U+01A0-01A1, U+01AF-01B0, U+0300-0301, U+0303-0304, U+0308-0309, U+0323, U+0329, U+1EA0-1EF9, U+20AB;
}
/* latin-ext */
@font-face {
  font-family: 'Montserrat';
  font-style: normal;
  font-weight: 700;
  src: url(https://fonts.gstatic.com/s/montserrat/v26/JTUSjIg1_i6t8kCHKm459WdhyyTh89ZNpQ.woff2) format('woff2');
  unicode-range: U+0100-02BA, U+02BD-02C5, U+02C7-02CC, U+02CE-02D7, U+02DD-02FF, U+0304, U+0308, U+0329, U+1D00-1DBF, U+1E00-1E9F, U+1EF2-1EFF, U+2020, U+20A0-20AB, U+20AD-20C0, U+2113, U+2C60-2C7F, U+A720-A7FF;
}
/* latin */
@font-face {
  font-family: 'Montserrat';
  font-style: normal;
  font-weight: 700;
  src: url(https://fonts.gstatic.com/s/montserrat/v26/JTUSjIg1_i6t8kCHKm459WlhyyTh89Y.woff2) format('woff2');
  unicode-range: U+0000-00FF, U+0131, U+0152-0153, U+02BB-02BC, U+02C6, U+02DA, U+02DC, U+0304, U+0308, U+0329, U+2000-206F, U+20AC, U+2122, U+2191, U+2193, U+2212, U+2215, U+FEFF, U+FFFD;
}

Now to Montserrat. If you download the font from Google : you have inside the zip file the variable font files and those static font files and indeed the internal Font Name is: Montserrat thin.
if you look at : https://caniuse.com/variable-fonts you see that it is now quite possible to work with variable fonts. Whether you need all these features – and Montserrat is one of these lavishly equipped variable fonts – is up to you to decide. If only a few fonts (300, 400, 700) are needed on the website, I think it is better to use the static fonts.
And comparing the difference between normal and italic Font it seems there will be no big difference on browser rendered italic font and embedded italic font. So it might be enough to use only those static font files.

Here are both zip files prepared to upload to enfold font manager:
( all will have ttf and woff2 inside – that will be enough for all browsers (ttf as fallback if there are very old browsers only on users desktop installation))

• Montserrat varible: Link
• Montserrat static: Link

on Font Manager it will look like this ( choose or use both with this https://kriesi.at/documentation/enfold/typography/#using-variable-fonts )