Huge 100ms FPS spikes for Canvas.BuildBatch - UGUI

Hello,

we are getting extremely high FPS spikes for our canvases when using UGUI, around 100ms per X seconds. Not sure if this is bug, I have read old posts mentioning this, bot nothing on newer Unity versions mentioning this Canvas.BuildBatch

This is on unity 6000.0.23 on macos m3 max, so its quite a beefy machine.

Any ideas please?