Hi Giedrius and welcome!
I'm sure one of the Pico team will answer, but it might be worth trying to change the file name (using Save As) as well as maybe some text in the details section (not sure how Pico have got duplicate detection setup), otherwise you could post the new wave form here as an attachment or directly to email@example.com
, and ask them to upload it, and investigate the bug!
Not had this myself, but clearly it's not right, and the ability to amend or update an upload is important.
I hope one of those options helps