Something weird happening [active cursor appears displaced by one character]

I have been using LibeOffice for years and suddenly have a problem I have never seen before. The active cursor appears to be in one place but in reality is slightly displaced by one character. This makes typing and editing extremely slow as I must second guess where I really am. It happens in both new documents and old ones I saved from way back. What on earth is going on?

What on your computer is going on? Without any technical details, we must rely on our crystal balls. Unfortunately, mine is at the wizard’s shop for maintenance.
OS name, exact LO version and save format?

I just had a very strange problem with LibO Calc V25.8.4.2: (Win 10)
When I entered a formula containg a comparison using <> for NOT_EQUAL the comparator was replaced with '> and didn’t work, of course.
My guess was user profile corruption. Seems I guessed right.

So is there something I should do in LibeOffice Writer?

If you find something you can do in (for) Writer that’s ok. I can’t suggest such a solution in detail because the issue is kind of unique…

My comment suppposed a corrupted user profile.
You may check if your issue would vanish with a cleaned user profile going
>Help>Restart in Safe Mode``....
If this is the case, you need to follow a trace like

  • Where’s my user profile located? (Default depending on OS.)
  • Rename the user folder user.bak (e.g.).
  • Start LibO again just to create a new “default” user profile.
  • Come back if you need help with restoring some not afflicted parts of your previous profile like AutoText, Sripts, ...

I don’t understand. You think this problem is in my OS not in LibeOffice?

No, he describes, where you can find the user profile of LibreOffice in your file-system to reset it:
https://wiki.documentfoundation.org/UserProfile

I told you that the problem probably not is in Writer, but in the user profile. The UP is created by LibO when it just was installed, and is changed by many actions of the user like defining AutoCorrect settings or User scripts ot AutoText entries ...
A corruption of the user profile may be caused by something like a premature closing down of the computer or a electricity blackout or even a hardware (RAM) error ...
I told you how to get a provisional diagnosis concerning the question “Was it actually UP corruption?”
I’m not an “expert of everything” - and I don’t have access to your computer.

Sorry. I thought LibreOffice was uniform across different OS.

I have PCLinuxOS. Does that mean I have a different LibreOffice version to everyone else?

The properties window won’t let me screenshot it. It says 25.8.1.1 (X86_64).

First, this is not a solution to your question. You should have clicked Comment or the 'call out" icon below my post.

Yes, version management proceed at its own peace across platforms and users are not compelled to follow changes. Some prefer to keep their beloved stable version.

Still missing: save format.

By the time I wrote this comment, @Lupp made a valuable hypothesis.