Hi Helder!
I never run into this issue with AET, but this reminded me of a very similar problem with EEWB. So you might want to take a look at those OSS notes:
1086848 - EEW enhancements cannot be transported
1820963 - EEWB Problems After System Copy
Second one seems to say that AET is very similar to EEWB in this regard... so those reports might be useful (see PDF file attached to the first note with an example of your exact scenario).
Cheers,
Nick.