Good to know actually. I never considered that you had to also “flag” the stash files as well as I’ve never messed with it that deeply.
Tho it should also be mentioned that if he is not using GD Stash at all then that means he also hasn’t flagged his character properly either, which means there are going to be “issues” unless he does so.
Edit: that is, assuming, that he was also transferring a character along with stash files. I suppose he might simply be just trying to move stash files only.