Since the 2018 update, most of the AAFs and some OMFs I import into ProTools will have delayed audio clips. Usually the clips are in relative sync, but occur several seconds later in the sequence than they should. This is a bug that used to occur before the 2017 update and largely seemed to be fixed, only to return again in 2018. Whatever you changed in 2018, it broke AAF/OMF export again.