Can't change case in the Term lists (and changing it in the item does not flow through to term list)

I used the Shift F# to change several author entries that I had from upper to mixed case

The bibliographic record is now correct

The term list was NOT populted with the correct case. Instead the upper case version is there. When I tried to edit the UPPER CASE to Mixed Case the OK button became greyed out

What is going on?

TIA/gary

(X6 Windows)