WodPress 5.3 change to Gallery Block structure

see Gallery block markup update

The gallery block is now wrapped in a <figure> element as well and may optionally contain a <figcaption> as a caption for the whole gallery.

Themes can style the caption using the classname .blocks-gallery-caption. The markup change will affect any themes using chained selectors such as ul.wp-block-gallery to style galleries. Themes should now instead use only .wp-block-gallery to style the container and the new .blocks-gallery-grid classname to style the ul element itself.

My galleries had wide width selected and all look fine until you update the post and then they revert to the normal narrow width. I am looking into temp CSS fix now.

Sorry I don’t have a link as the site is on development server.