Volume increases when I double a sequence

I double length a 4-bar sequence and the second half is louder.
I removed all the insert effects.
There are no submix effects.
I went through the list edit and there are no automations that would increase the volume.
Is this a known bug? I can't find anything on it. And if it is, how can I fix this?
Thank you in advance.

I’ve seen that when I double a track but not a sequence.

If there are not too many tracks in the sequence, a good work-around may be to copy events. Because this can only happen on a per track basis, it might get tedious.