Duplicate check doesn't work sometimes

It seems like invisible characters ruin duplicate checks.

What add-on are you having this issue with?

None, it says bug reports go here too.

That’s easier. There are 2 kinds of duplicate-checks – automatic when you’re adding notes (Adding/Editing - Anki Manual) – and manual in the Browse window (Browsing - Anki Manual). But both of them will only find fields that exactly match.

If you know you have “invisible” characters in your fields, you could consider removing them before searching for duplicates.

I’d recommend a project for anyone if they want to ignore empty characters that don’t change how the text actually looks so that duplicate checks are more reliable. No harm in adding extra cards i guess more studying but still.