Same issue here.
I didn't use Mac for few months. Before that, it worked well. Then came back to my current Mac, installed new version of Libreoffice. And noticed it sometimes freezes.
When it reaches 95+ and then even bit over 100%.
Just hangs there. I wait, wait, wait, then it seems to get bit better, but when I try to shut it down, it hangs again.
Finally get all files closed, check Activity Monitor and Libre Office is marked non responsive. Sits there for some time, then shuts down. Open it again and everything seems to be working fine. Until next time.
I used the link it gave me when I clicked on old Libreoffice's Help>Check For Updates. That would mean it is the real deal and not some spyware? LibreOffice has never acted like this before. Does anyone else have any idea if this is some new change they made?