A fix for this issue has been released.
If adding multiple subjects against one Curriculum, the TA grade will get overwritten for every subject
If a school has set up a Curriculum Tracker with multiple subjects, there is an issue where the Teacher Assessment (TA) judgments are set, it will overwrite that same TA setting for each subject.
Workaround
A possible workaround for this is to create a separate Curriculum for each subject.