MaterialExpressions being picked up by GatherText commandlet

I’m successfully running GatherText to import/export a .PO file for localization. In the .PO file I’ve noticed a few lines similar to this:

#. Key:	Vectors
#. SourceLocation:	/Game/Effects/Alien/Portal/Effects/AlienPortal_Lightning_Mat.AlienPortal_Lightning_Mat:MaterialExpressionConstant2Vector_0.MenuCategories(1).MenuCategories
#: /Game/Effects/Alien/Portal/Effects/AlienPortal_Lightning_Mat.AlienPortal_Lightning_Mat:MaterialExpressionConstant2Vector_0.MenuCategories(1).MenuCategories
msgctxt "MaterialExpression,Vectors"
msgid "Vectors"
msgstr ""

These strings are clearly coming from some particle effect materials we have, but I haven’t been able to locate the actual usage of the string “Vectors” in the material blueprint.

Ideally I’d like to exclude this string from being localized. For most strings in our other assets, I am appropriately marking them as CultureInvariant. I was going to do that with these but can’t actually find the FText field that seems to exist in MenuCategories.

I could just add the specific materials to the ExcludePathFilters in GatherText, but I wanted to check to see if there were other options before I do that.