insulated walls and wall toggles

Today I was fitting a bracket to a plasterboard wall using a Ramset Super Wallmate toggle — normally rock-solid, never had one fail to install properly before. But this time, it just wasn’t working. I spent what felt like a solid 10 minutes trying to figure out what the hell was going on. The screw just wouldn’t go in straight.
Took it out of the wall — worked fine. Put it back in — same issue. Eventually, the helical thread stripped the plasterboard, and that’s when I finally caught a glimpse of the culprit: bloody insulation in the cavity. Even after prodding it away, it took ages to clear enough space for the toggle to actually open and work. In the end I installed a plate of plywood across studs and then screwed into it. Probably should have done that in the first place.

Who's come across this problem and how did you solve it?