Possible bug in promo box or help?

Hi all,
when I add a promobox, in certain conditions, a </p> tag is added without any opeing <p>, and in nosense places (for instance, at the beginning of the box). The w3 validator detected it.

To be honest, I don’t know if I’m doing something wrong, or how critical this is. The browser did not complained.

This is the code generated (simplified):

<div class='av_promobox avia-button-yes  avia-builder-el-9  el_after_av_one_half  el_before_av_textblock '>
<div class='avia-promocontent'>
</p>
<h2>Title</h2>
<p>text</p>
</div>
<div class='avia-button-wrap avia-button-right '><a href='...' class='avia-button avia-icon_select-yes avia-color-blue avia-size-large avia-position-right '   ><span class='avia_button_icon' aria-hidden='true' data-av_icon='' data-av_iconfont='entypo-fontello'></span><span class='avia_iconbox_title' >PRESS ME</span></a>
</div>
</div>

And this is the shortcode (copied from the debug box):

[av_promobox button='yes' label='PRESS ME' link='page,332' link_target='' color='blue' custom_bg='#444444' custom_font='#ffffff' size='large' icon_select='yes' icon='ue86d' font='entypo-fontello']
<h2>Title</h2>
Text
[/av_promobox]

I have troubleshoot that, if the text start by a paragraph and not by a header, it does not happen.

Should I change anything or forget about it?

thnx in advance