ALB textblock strips out span-tag

Hi,

in a page, created with ALB, I have added a textblock with this content:

<h1>This is a h1 Headline</h1>
<h3 class="stripes"><span>This is a subline with stripes at the end</span></h3>

After saving the textblock and saving the page, it looks correctly like this:

But when I reopen this textblock, then the <span> </span> has been stripped out – and therefor the output in frontend is wrong:

Used CSS:

.entry-content-wrapper h1 {
  border-left: 6px solid #d3b9b1;
  color: #b5b5b5;
  font-size: 50px;
  font-weight: 400;
  padding-left: 20px;
text-transform: uppercase;
letter-spacing: 1px;
}
h3.stripes {
  background: url("../images/eigene/stripes.gif") repeat-x scroll center 10px !important;
  padding: 1px 0 0 0px;
  width: 100%;
  text-align: left;
  margin-left: -10px;
}
h3.stripes span {
  background-color: #FFFFFF;
  color: #b5b5b5;
  font-size: 15px !important;
  letter-spacing: 2px !important;
  padding: 2px 10px;
  text-transform: uppercase;
  font-weight: normal;
  vertical-align: top;
}

Why is the <span> tag always stripped out when I save the textblock after editing it?

I use the newest ENFOLD, WP 6.2.2, classic editor and I have this on my sandbox site as well as my local site.

The fact, that span tags have been stripped out, is an old issue, that others had, too:
here –>
and here –>