Refreshed my creative/copy in a campaign that was performing well - same angle/message, just a refreshed video
Added a new ad set + ad although used the same lead form.
Performance was decent first 5 days, then 2nd four days CTR has been the same (1.6-1.7%) although lead form CVR dropped from 8% (9/111) to 1.3% (1/73). Is this Facebook "learning" and being weird or is there something to fix?
I'm thinking that I went wrong by creating a new ad set - but just wanted to put this here to confirm