Wappler Version : 7.3.6
Operating System : macOS
Server Model: Wappler Local Server Node.js
As shown in video, I’m unable to select $_POST.inputvalue in form file upload.
Looks like after every Wappler release, we’re getting new bugs as surprise gifts — guess the team brought back more bugs than memories from their summer vacation 
yes this is a known bug that happens on subsequential data field selection in the picker. If you just open it and select it directly it should work fine.
For the related bug see:
Fixed in Wappler 7.4.2