Confirmation of silly vendor trades - unable to unstack in vendor trade

For about the 4th time I have just made the same mistake on xbox. it is just too easy a mistake to make,

I wish to trade several level 20 gems with a prism to create 20% quality. I place one gem in the trade (yiu can’t do three at once) and then I hit B to unstack the prisms, I follow with A To confirm the section of 1, the Default unstack. However in the vendor trade, the unstack command B is ignored and of course then the A Triggers the trade, which means my weeks of levelling of the gem is discarded.

During the course of the game, we unstack a LOT taking one item from stash for example to place in inventory. This is “muscle memory”. This is so wired in, that even being aware of this problem, I still fell into the trap.

There is no reason why anyone would want to trade a levelled gem for a scrap, please put up a confirmation dialog, or simply fix the broken ‘can’t unstack” issue.

I do think they should let us unstack in Vendor trade, but here's a tip to help keep you from doing this again:

Always put the GCP(s) in the trade window *before* putting the leveled gem(s) in.

I've been following this habit for many leagues now, and it has saved me on more than one occasion.