@MiniMattersEL , Y the presenter layer? The presenter layer is not able to switch a cropped image to fullscreen. Maybe it never will. So, try this:
Create your own presenter, made of pip-windows:
It works like this:
https://drive.google.com/file/d/1103h_yCJLkowBrn2KhE5dqsUPWKwly7a/view?usp=sharing
It need not to be so colorful (or with that fat borders; I’m keen on… 
), but it seems to be that I liked it. If you need more fullscreen inside, just do the same slide more often into the variants (but with different positions).
BTW, If forward/backward should work exactly simultaneously, you have to use 2 automation-layers. One for switching the first, and one for switching the second layer. Combine it with a Layer Set to activate both script-layers exactly simultaneously.
Or you could also do a “sleep(3)” command between the two other commands, so a total new effect appears. Or for backwards-switching you could change the position of both commands to have a more natural look while switching backwards.