Qt Creator Webassembly plugin prints full program in text

Compiling the simple calendarwidget example on webassembly with qt creator's webassembly support takes 28mins on my machine, because qt creator mostly sits and does this by default: https://imgur.com/a/dcEcv7s

Perhaps this was a debug option that forgot to be turned off?

Update: problem was wrong emsdk version (too new).