i use addon for subtitles, called subclub.eu. and with CE18.1 i can’t download subs, it just wont load and unpack them. in LE 17.6 i did not have that issue.
CE doesn’t handle 3rd party addon issues, you’ll to contact the addon author and ask them to fix it.
It’s likely that the addon needs to be updated to support Kodi Leia.