I already posted this a while ago, did not Tag it, do not know ho to add Tags to old Posts, so once again as I now know it is reproducable on several machines.
-Use Clip gain on Audio Part, for example -10 dB
-cut Part in half
-use spectral Layers on second part (and actually edit with it)
-create crossfade between the parts
RESULT: ARA part is now playing with -20dB clip gain.
The clip gain is calculated twice when crossfading into an ARA-Part.