It’s been a month since I have this issue too. I first thought it was the SD card, the power supply, etc.
Today I monitored kodi and systemd logs by watching TV series and movies while connected by SSH and I noticed that while Kodi was frozen, my ssh sessions where still responding.
By making a new ssh connection or by closing one that was already up, Kodi would unfreeze and catch up some buffer.
After each « unfreeze » I see those lines in journalctl :
Nov 28 22:29:50 osmc systemd[1]: systemd-logind.service watchdog timeout (limit 1min)!
Nov 28 22:29:50 osmc systemd[1]: Unit systemd-logind.service entered failed state.
Maybe it’s a lead…