Last known information

The last try to fix triggers using last known information by Hellfish has some side-effects:
When I use Giant Growth on a creature and then Unsummon it, it will retain it's bonus in my hand
.
I know this has been a problem for a long time now, but has anyone a good solution for this?
When I use Giant Growth on a creature and then Unsummon it, it will retain it's bonus in my hand

I know this has been a problem for a long time now, but has anyone a good solution for this?