i think i know why this is happening: someone has made an assumption about aspect ratios. my phone is tall and narrow, so anything locked to 16:9 will be stretched or have gaps.
For some reason i had to choose android mode and that fixed the issues with the app rendering area being too small. It was set to iphone mode for some reason... Check your settings.
I believe this is the same bug, it has been around for a long time now