I must admit I haven't tested this in ages. We're going to lose QuickTime in September when the new Mac OS comes out, so I wouldn't really recommend using QuickTime VR for anything in the future. That said, I'll take a look and see if something can be done without too much trouble.
Get the Sony ALPHA 6300 or 6500, its just under a grand, it is the best camera out there in that range, hands down! I even know people who have downgraded from the A7 because of the dynamic autofocus of the 6300/6500, which is amazing if you want to do gimbal/drone shots.
let me know if you want to play with mine before deciding
it will give you berautiful 4k sLog3 footage so you can play with the new LUT stuff in izzy. And it does 100fps at 1080 which is fun
I tested the file you PM'd me and I then tested a few other files that were encoded at the same time and in the same resoultion as the one causing me trouble and they all played fine. Perhaps it is just this single video that has something wrong with it.
Regardless, I will double check the HAP codec as you mention here and also try re-encoding the individual video that seems to be having this issue.