Trying to set Theme fails

[skrolikowski]

Describe the issue

Trying to upload new Theme works find, however setting it to Current Active causes unexpected 500 error. See screenshot.

To reproduce

• Upload new Theme.
• Wait for it to upload and show then set it as Currently Active.
• View console for error.

Screenshots

Version and browser

Version: v6.0.0 Beta 3
Browser and version: Chrome 79....

Bug report checklist

• I have filled out as much information as I can
• I have detailed how the issue can be reproduced
• I have searched for existing issues and to the best of my knowledge this is not a duplicate