Libre Calc suddenly quit auto-calculation

Now I have to hit F9 any time I change or add an entry.
I’ve used Libre Office ever since it branched from Open Office, but this is a recent problem.

I’m using Win7 (English) and I’ve tried LibreOffice 4.23 & 4.24 (Portable Versions), and tried reinstalling several times, but no help. Just to check, I tried Gnumeric to see if it was something with my system, but the problem only shows up in Libre Office Calc. Can anybody enlighten me?

You also can have a look if the (default) customization of the F9 key is broken by whatever the reason is.

Tools > customize > keyboards > window “shortcuts”
Click into this window and strike F9. If you do not see “Recalculate” you can reallocate using the Modify function.

Should you see F9 - Recalculate, we have a bug. Please report it at: https://www.libreoffice.org/get-help/bug/

I tested LibO 4.2.4 / XP and F9 recalculates.