BP SET nodes for FGameplayTags do not respect category filters, instead the dropdown shows an unfiltered list of all gameplay tags.
Given the MyValue property decorated as follows:
UPROPERTY(EditAnywhere, Category=MyCategory, meta=(Categories="MyCategory"))
Blueprint SET node for MyValue would contain a dropdown list that is limited to tags that match the filter (MyCategory).
Blueprint SET node for MyValue has all gameplay tags in the dropdown list regardless of category.
create a C++ actor class with property MyTag of type FGameplayTag
decorate the UPROPERTY with meta Categories with any filter string
build and launch the editor
create a root GamePlay tag with you filter string and some child tags
create some other GamePlay tags that are not under the matching tag
create a blueprint from the new actor class
notice you can edit the default value of MyTag and the UI restricts you to matcing tags (filters working correctly)
drag the variable onto the blueprint and create a SET node
click the tag drop down in the SET node and notice it shows all gameplay tags unfiltered (filters not working correctly)
There's no existing public thread on this issue, so head over toAnswerHub just mention UE-67193 in the post.