Serious bug uploading images on 3.18.0

Hi!

When you upload a picture via a ACF Frontend Form it appeards to be ok but when you want to edit again you realise it creates a hidden file on the the server. It changes from “mypicture.jpg” to “.jpg-1.jpg”.

It not only creates problems to visualize but also the server thinks there’s an attack with this hidden files.

Please take a look!