As a work around, you could populate the empty track spaces with empty region, so each track is filled with regions. Then glue/merge (join) all the regions on the same track, thus creating a long region covering the project's (track's) length. Doing same for each track. You should then end up with equal length exported audio files for your tracks.
To update, you could obtain same from your Apple Store account.
Before updating, it is highly recommended to backup your current LPX version and projects...
LogicX 10.4.8 ( & 9.1.8),MainStage3.4.3
MBPro 17", Core2Duo, 8G, OSX 10.12.6
MacPro, Xeon 6Cores, 64GB, OSX 10.13.6
ULN8, MOTU MIDI TP-AV, C4, Eucon McControl, KorgNano, Novation SLMkII
AAS, NI, Celemony, Spectrasonics, Korg, MIDIQuest, etc...
PC, iPad3(V-Control & LogicRemote), AtariST(Notator SL), Several vintage gear