Hi PaQ - thanks, I can repeat it now in the Sep-21 beta. Sorry I was focused on that already-done fillet there, I don't need a pre-filleted version.

Seems to be a bug in the filleter where it is messing up the trimming boundary on that face that then looks weird. The odd thing is that face getting messed up when the actual fillets are done on the opposite side and not connected to it.

One quick work-around for now to patch up this object, is to select the face that is messed up, and use Edit/Separate to break it out from the main model. Then hide everything else, select the 2 edges of the messed up face and hit delete to untrim it and that fixes that face up, then you can show the rest of the model and join that piece back in again.

It looks like somehow the seam edge of the old fillet there was discarded for some reason, making that particular surface have an invalid trim loop.

I may not be able to dig into it in more detail until after the next beta is out.

- Michael