Hello Ashley
I had two more feedbacks from people with the same bug. The way they play is clear, they force the character on the wall during a walljump.
Even so, I couldn't represent on any of my 3 computers with different performances (a good one, a medium one and a terrible one).
After MANY tests with one of the people who had the problem, this started to happen only through FireFox. As you said that the browser would theoretically have no difference, I made some more adjustments to the advanced engine settings.
Apparently, the only setting that "fixed" the problem, was to change the "Use worker" option to "No", and "Framerate mode" to "Unlimited".
I tried the separate settings and were unsuccessful.
What can that mean? That the computer is skipping collision frames?
The character clearly teleports from one side of the wall to the other. It appears that the program tests the player's collision only when it is already inside the solid object.
I am not accusing a bug in Construct, but trying to understand what may be happening, or where.