You’re right, I did not check all my domains, I assumed all were concerned, but the one with Discourse can be ignored.
That’s said, I’ve also figured out how to force renew:
cd /var/discourse
./launcher enter app
"/shared/letsencrypt"/acme.sh --cron --home "/shared/letsencrypt" --force
exit
I don’t know if there is a more direct way, but it worked after refreshing website cache.