Hi,
So this is indeed discourse-calendar (it’s installed on your instance).
“no” will be fixed by FIX: quotes no as it's reserved yaml keyword by jjaffeux · Pull Request #80 · discourse/discourse-calendar · GitHub
“nyse” will be fixed by DEV: ignores NYSE (new york stock exchange) by jjaffeux · Pull Request #79 · discourse/discourse-calendar · GitHub
I can’t repro the UK bug.