Frustration with gem converting supports

wereotter

Say I'm using a two color planeswalker, and put down a support that concerts gems to my colors. We'll go with Battlefield Forge in a Nahiri deck for the example, but it happens with and two color converting support.

My opponent's turn has ended and the field is set up that I'm about to match 5 white gems... then Battlefield Forge turns one of them red, so I'm now out a great match for a much worse one. Even worse I've seen it completely rob matches where there's only a 3-gem match in red and the support makes one of those red gems white.

I feel like these supports should ignore gems that already are either color when selecting gems to convert.