Strange Reverbish Sound

i have a really strange problem with my xdj xz

i recorded last week a 2 hour set with also some self produced tracks... now everytime when a track kicks in which i made by myself it sounds like really bad quality. and no my tracks arent shit hahahah xD the problem is that its sounds everytime like there is a slight reverb on it.. almost like it sounds out of a barrel or so xD if i mix internal then there is no problem and it sounds like it should
but when i mix external then the problem comes again. i was first thinking that maybe the the bitrate or so is wrong but all tracks from the set are AIFF files in 44100/16bit

has anybody had the same problem or maybe an idea what i should check next??

by the way im working with a Matebook X Pro 2018 and win 10 Home on it

thanks in advance