Luke, do you have access to both the old version of logic (10.3.1) and the new version (10.5.1) ? It would be interesting to have a look at the different midi files and compare the two. If you create a simple automation with a few changes it’s possible to diff the files.
You can post it here by running xxd command in the Terminal: xxd old_logic_working.mid
I actually wrote a converter tool myself to solve the issue.
I found out Logic somehow write a very high ‘end time’ to the first tempo track in the MIDI file.
My converter just takes out this ‘wrong’ information and rewrites the MIDI resulting in a perfectly timed MIDI file.
Still annoying Logic isn’t correct with this by default though.
That’s interesting. I haven’t been able to look at it for a while but I would like to create a similar tool. Jeroen, if I understand you correctly did you just remove the end time midi event from the Logic exported file and that solved the issue, did it? do you mind sharing the code?