adamg’s steps do not always solve the problem but this does almost for sure: here
his steps are not always verified, didn’t work for me
edit: don’t know why CE deleted my the only fix for me, manual:
try these steps
-
ssh
rm -rf /storage/.kodi/addons/packages
rm -rf /storage/.kodi/addons/repository.coreelec -
install nightly update
-
install again stable update
for me problem solved