STEPS TO REPLICATE

1. Go to Site administration > Advanced features and set Enable web services to Yes
2. Go to Site administration > Server > Web services > Manage protocols and enable REST protocol
3. Go to Site administration > Server > Web services > External services and Add an External service
4. Set the following fields:
   Name: Test Service
   Enabled: Yes
   Can download files: Yes
5. Add functions to the service "Test Service"

EXPECTED

The user sees the form to add a new function.

ACTUAL

The user sees error:

Coding error detected, it must be fixed by a programmer: Missing implementation method report_insights\external::set_fixed_prediction