Actually just answered my own question. If anyone else is having this problem, the PlatformPro admin CSS has this block around line 1573:
.hl, .hl2 {
background: url(../images/hl-dot.gif) repeat-x top;
clear: both;
height: 2px;
overflow: hidden;
width: 100%;
}
The “height: 2px;” is killing ALL buttons for ACF, not just the gallery buttons. Comment it out or override in another stylesheet and you should be fine.
