Only some tables will not open

I have a database with a number of tables. All of these tables will open in LibreOffice in Ubuntu. They will also open in Windows OpenOffice. I have checked Java, the computer is up-to-date with Windows, and I have twice removed and reinstalled the latest LibreOffice.
The tables were created by copying from .ods, and the fields then changed to match the actual contents (INTEGER, TEXT, etc). Now, if I try to change a field the program freezes…sometimes. If I try to open a table some will be OK and some will freeze.
This database was working perfectly 6 months ago, and the backup is no help.
I am sure that if I sent one of the tables it would be fine, as I can open them in two other ways. Something is corrupted, but I have no idea how to find the problem.

That leaves problems in your profile untouched: You could try Safe-Mode or renaming the profile.

Why? To much changes since last backup or also no access?

PS: There is also the following thread, so it might be useful to file a bug on the topic:

Thanks for the excellent advice. The primary backup db had the same error. I have a one year old version of the db on a second backup that has the same problem. I tried Safe Mode and renaming the Profile folder, to no avail. When I converted to Firebird, I got this message : “The document contains embedded HSQL data, which is deprecated”, i.e. not “approved” in some way. The Firebird db is perfect.

I suspect that Windows or Java updates may be where the problem lies, but I will try an older version of LibreOffice next to test that.

I chose a random older version ( 24.2.0.1 (X86_64) Build ID: b4d45829793cddfe67b58a53f495528c75738d8a) and the problem was solved.
So, the problem lies in the current version of LibreOffice.
How do I report this as a bug please?

https://wiki.documentfoundation.org/QA/BugReport