Quick background stats on 2 systems.
Old moodle is version 3.6.2 , ubuntu 18.04 php 7.2.32 msql 5.7.33
New Moodle is Version 3.10 ubuntu 20.04 php 7.4.3 mysql 8.0.23
The issue: When i backup a course that was a bit older probably from moodle 2.8 and carried forward. the process goes through and says everything and all activities have been backed up fine. Then when download the .mbz file and upload it to the new server all is good. However during the restore into a new course process some activities and content are dropped completely and some activity text is altered. as an example in one lesson an entire audio was dropped not even a place holder between activities was there. And an example of the text issue is in one lesson that did import the audio the text for the lesson said "listen to items 0-30". However on the restored lesson it said "listen to page66"
So some weirdness going on that i cant seem to find the answer too in other posts.