Hi there,
It’s not really our responsibility to catch all exceptions when plugin contents are involved and the question is more of a general CSS help rather than theme/premium plugin related question.
For this case you can try adding this CSS:
a.ugb-button {
border: 0 !important;
}
Basically, for links that you do not want to underline, you’d need to find the specific class and the above CSS to it. Similar to this as well:
https://generatepress.com/forums/topic/specific-layout-for-posts/#post-1133266
Or, you can add the class underline
to the links you want to underline, then target your CSS like this:
.entry-content a.underline {
border-bottom: 1px solid #000;
}