I tried to open a file from the "recently used files" - list. This file is on a disk which I hadn't mounted yet. LibreOffice closed and restarted the PC without further notice.
Please test with version 5.3.3. If you don't know how: https://wiki.documentfoundation.org/Installing_in_parallel/Linux Set to NEEDINFO. Change back to UNCONFIRMED, if the problem persists. Change to RESOLVED WORKSFORME, if the problem went away.
I tested with Version 5.3.3. Now an error message appears that the file is not available, which is true.