Sorry I didn't check back with the thread for a while.
At first I had freezing problems when opening a document, but then traced it to the fact that I was opening a file shared from my Mac Mini on OS X 10.4 (to my MacBook Pro with El Cap PB2). I believe I had to change the share from read to read/write.
I'm actually still on OpenOffice for now, but am planning to move to LibreOffice in the future. So I didn't test LibreOffice extensively. But both were freezing with the same symptoms before I changed the permissions on the share.
I suppose - technically - that it should still function on a read-only share. But since I have no need for such an office document share right now, I didn't think of it as a bug, but rather a user configuration error. Perhaps I should still report it?
Sadly all the files are on my MacBook direct, not via a share. I am experiencing the freezing and it seems to recover for a while and then freeze again randomly.