Unless I’m mistaken or have been doing it wrong for years: at some point in the last couple of weeks or months, Google appear to have changed Gmail so that you can no longer filter like: from:noreply@example.com and have it just give you emails ONLY from that specific address.
You now need to do from:"noreply@example.co" otherwise you can get mixed results (in my case, the search was including emails sent from a different address, but in the footer of the email it had the text “noreply@example.co” – so I can only guess it was including them in the search??)
I had a couple specific workflows to filter email & noticed that it was including random things in there. Again, I could be wrong here but I’ve been doing this for at least a year and I’ve never noticed this issue before until recently. It seems silly that it’d require quotes when filtering on a from: – which, to me, implies you don’t want any fuzzy search stuff going on? But anyway, using quotes fixes it.