Graphics Builder Automation (GBA) - Can't extract or enter some substitutions

Hi,

Have been using GBA to extract and update substitution text automatically from a lookup before/after.
However - it looks like there may be some limitations in GBA that hamstring this process.
The specific example is in the attached image, where a substitution is used in the Privilege field but GBA can only Get/Put an Int.

Anyone know a workaround for this?