Password Protection settings not saved in Calc

I just updated to on Windows 10.

When I password-protect (File->Properties->Security->Protect…) an .xls file and save it, then close Calc, but when I open it again, I am not asked for the password. When I go to File->Properties->Security->Protect again, the “Protect…” button is there (Not “Unprotect…”,) and when I click on it, there are no (obscured) passwords on the Password dialog that opens.

I also note that, when I click “OK” on the Password dialog, the “Record changes” checkbox on the Properties dialog always gets checked, even though I have NOT checked “Open file read-only” or “Record changes”. When I then un-check “Record changes” the “Unprotect…” button changes back to “Protect…”

I have successfully password-protected files with past versions of LO, and when I open them with, I am asked for the passwords.

What am I missing here?

Am I doing something wrong, or is this just broken?

Okay, I figured out how to password protect a file again…

I have to use “File->Save as…”, not “File->Save” or the “Save” button, and click “Save with password” on the “Save As” dialog.

Apparently, “File->Properties->Security->Protect” does something different???

This is too confusing.