in Version 2025.3 (219382)
Changing the colours in the inspector for multiple symbols have unexpected results. The symbols are in a library document also created with the beta.
Hey Gael,
Thanks for reporting this. It seems that the bug’s triggered when you click and drag to select the override color. If you click without dragging, the bug doesn’t trigger.
It’s not related to libraries, the issue happens in the library document as well as in documents using symbols from it. It also happens when you override a single symbol.
Here’s a video of how I reproduced the bug:
I’ve created an internal report, shared it with the team and we’ll let you know of any updates 
Diggin a bit more I found that having the background fill incluided as content can contribute to the issue. Disabling it won’t fix the bug completely, but it will help get more consistent results.
In this demo, I disabled the background fill as content. I no longer get the black square background on the icons, but the bug still triggers and can affect all the layers in the symbol
We’ll keep looking into this