I tried my firsts exports and I have always the same problem : it seams that a little part of time at the end of the session is not exported : when I play my FLAC file, it misses a part of second at the end.
Maybe try moving the end (“fin”) marker just a little bit more to the right (by the amount of sound you are missing)? If you are having a longer reverb tail or similar (unclear from your screenshots), you should move the end maker accordingly, otherwise those slower fade outs might be cut off, as rendering stops hard at the end marker.