mmmmmmmmm maybe not related but i had the same problem with a track from RealBand. The individal wav files lined up perfectly in a friend's DAW. then he wanted to double the kick drum. so using the drum grid editor i dd a midi kick drum beat 1 of the bar and fillled a vacant RB track. exported as wav and then he pasted into his DAW only to find the drum didn't line up by enough time to be noticeably out. sample rate and bit depth the same on all tracks. can't be because it was midi because the strings track was midi. lined up perfectly in RB but the wav file was out in his DAW.

maybe user error i some form but what exactly escapes me