enfold burger menu opens but it is empty

After updating to WordPress 5.6 and updating all plugins / themes the menu for smaller devices (tablets/smartphones) open but it is empty.
If i look into source code it is really empty:
<div class="av-burger-overlay" style="display: none; opacity: 0;"><div class="av-burger-overlay-scroll"><div class="av-burger-overlay-inner"><ul id="av-burger-menu-ul" class="" style="padding: 122px 0px;"></ul></div></div><div class="av-burger-overlay-bg"></div></div>
I read several entries in support forum but no measurement helps.
What i did:

Clearing cache
Turn on/off compromizing tools
deactivate/activate each plugin (one by one)

These are my Quick CSS entries:

.product p.wc-gzd-additional-info {
margin-left: 1rem;
}
.product p.wc-gzd-additional-info a{
margin-left: 1rem;
}
#woo_pp_ec_button_cart {
margin: 1rem;
}