I found out whats the problem:
GF block call a WP rest endpoint and when adding custom attributes to GF block, it reject it at the endpoint making the block broken in the editor.
This should be fixed as block developpers should be able to customize any blocks in the editor. In my case, ive added a show/hide block feature based on media breakpoints and this whats cause the problem.
This topic might be related as well: Error loading Gravity Forms block in Gutenberg