Board Thread:Support Requests - Getting Technical/@comment-29252070-20180719181254/@comment-168424-20180720213739

Unless you submit it, you'll never know. I've found that trying to guess what is happening under the covers is usually futile and wrong.

Galleries are supposed to play nice with other MediaWiki parts. Otherwise it should be mentioned in Help:Galleries, Slideshows, and Sliders somewhere.