Laggy zoom on videos with third party apps

Hello,

I’m facing a problem with my FP6 when recording videos with the back camera, on third party apps : when I’m zooming in, it becomes very laggy at some point, pretty often it even freezes completely. I think it happens during the transition between the two cameras (around x2 zoom).
I don’t have this issue with the selfie camera, and I don’t have this issue with the camera app (only with snapchat, what’s app and instagram).

I thought I remembered seeing this issue in the list of fixes of one of the updates, but it doesn’t seem resolved to me. Is anyone else having the same problem ?