While annotation lookup can be case insensitive, this does not make the terms themselves case insenitive

[mbakeranalecta]

For indexing purposes, specifically, {foo}(index) ... {Foo} will treat foo and Foo as separate index entries even though it look copies across the (index) annotation.

One way round this is with an annotations lookup file in which you do this:

{foo}(index "foo") 

This way the specifically value will be used for indexing both "foo" and "Foo"