Hey, looks like Xform PC -> Stop, PC, Start tries to work around the same program change timing problem by sending a sequence of stop, program change and start messages. It will soon be possible to have Midihub perform the inserting ‘stop’ and ‘start’ messages at the right place, so it should hopefully help with timing of program changes in your case as well.
Is the mapping between the Octratrack’s progam number and the M:C program number unpredictable? How many such mappings do you intend to have in your set?