Thanks for the tip.
However, it must have been something else:
Before I posted, I tried running writer (and other components) from console, nothing happened.
Worked in Windows for 2 days, then came back to PCLOS, now ran soffice from console, works as expected.
Ran it from the menu, works fine.
I'll never know what the problem was (unless the install requires a reboot... but no, that sounds absurd).