When editing prefab with multiple tilemaps and having different tilemaps selected in Hierarchy and Tilemap Palette tabs, tilemap Palette sometimes switches active tilemap to active in Hierarchy tab.
Also if in Hierarchy tab there is selected any other gameobject other than tilemap, It can sometimes cause Scene and Tile Palette winows to blink and resize for a frame.
I’ve tried looking to see if we had anything similar reported, but there was nothing found that describes the same problem you’re encountering.
I would like to ask you to kindly please report this issue via the Bug Reporter from the Editor and please make sure to attach your project, that would greatly help us out in troubleshooting the project and finding out exactly where it’s coming from. This also could help us in understanding if it’s a project specific issue or not.
To report a bug please follow the following steps:
Open the project where you encountered the issue
Reproduce the issue to verify that it’s still happening
Open the Bug Reporter from the processes toolbar (Help → Report a Bug…)
Fill out the fields and in the Description please make sure to link this Discussions thread URL