Specialization not marking as complete despite all activities being completed

Summary

Certain courses completed outside the specialization not leading to the completion

Content

Hello

We experienced a bug in 20a (we have since moved to 20B) where certain users were getting an error message completing an elearning course within a specialization. The workaround was to advise them to access that particular course through the learning catalog instead. However this has lead to a downstream issue.. 

Example:

Specialisation has 5 elearning courses.

User completes 4 within the specialization and the other one via the learning catalog due to the error.

The record for the specialization against the user is marked as 5/5 however it is not marked as complete.