Background Job ID 53887, Sentry Event ID (not available)

ShotGrid
#1

I’m trying to make calculated fields and get the following error:
Please pass on the following id for the error so we can trace what happened: Background Job ID 53887, Sentry Event ID (not available).
Not a valid human name

I even tried to re-create an already existing calculated field and received the same error.
Can someone help please?

#2

Found the cause - a ‘+’ in the field name.