does it maybe have something to do with it being a tracked field of some sort? (i.e. if you configured it to be a tracked field there IS definitely a low limit on the number of those you can have)
Here's an article that gives you a bit more information: https://one.workfront.com/s/document-item?bundleId=the-new-workfront-experience&topicId=Content%2FAd...
Thanks, @Skye Hansen! I think you are on to something here! After reading the article (and initially not knowing if or how we could be tracking fields), I looked at our setup.
It appears that we have 19 Built-In Fields and 281 Custom Fields being tracked. Is that linked to the question on the custom form that asks if we want any changes to that field, we want it noted in the Updates Section?
that's exactly it. I recommend you just use that functionality when you absolutely need something tracked... otherwise, looks like you have hit your limit.