From what I can tell you need to
Open Malwarebytes for Windows.
Click the Detection History card.
Click the Allow List tab.
To add an item to the Allow List, click Add.
Select the type of exclusion you want to add.
You will probably need to do this for PixelCharacterMaker.exe, H1.exe and H2.exe(H1 and H2 are external files that deal with converting the exported file to a .png) which are all in the PixelCharacterMaker folder