The issue was originally reported here: https://discord.com/channels/778915844070834186/1297991791387345010
It was supposedly fixed - as mentioned in these patch notes: #📣patch-notes message
In practice, it wasn't actually fixed and the FPS still tanks dramatically when staring at the effects mentioned in the original bug report's additional comments.
I'll add that the FPS drops are much more noticeable when having two game windows running side by side.
I also tried clearing the cache but the issue still persists.

