I've noticed a weird issue with the Jump Thru behavior. If a platform sprite is at a standstill to the left of the jumpthru tilebg without overlapping another the platform sprite needs to accelerate to a certain speed in order to move past it, but only if the platform sprite is moving right.
When moving left from a standstill the platform sprite passes through as expected. If the platform sprite is already overlapping a jumpthru tilebg then it will pass through all other subsequent instances as expected. It only occurs when not already overlapping a jumpthru tilebg.
Just get as close to the left side of the either of the teal platforms, and then press right. You'll notice a hesitation followed by a "pop" as you move past it. I assume it's because you're still accelerating even at a standstill, and once the platform sprite hits a certain speed it passes through.
I assume this is a bug due to the inconsistencies mentioned above.