After some time (15 minutes? 30 minutes? 45 minutes?) soffice.bin process starts to eat 100 % of cpu time (as seen with top utility). It stops after I save a document that is open. Autosave does not stop it, only the save command from the user.
Documents I use are text only, typically few dozen pages. I don’t know if the problem appears with shorter documents. I use odt file format and default settings.
LibreOffice version: 126.96.36.199.
hardware: Raspberry Pi 4, 4 GB
OS: Raspbian (Raspberry Pi OS), 32-bit, based on Debian buster
Exactly the same problem appeared on IBM T43 computer with Slackware 14 (OS) and a bit older LibreOffice version