When navigating to screen 2 from screen 1, canvas on screen 2 does not instantiate. When opening the app into screen 2 (preview) the canvas instantiates no issue. The canvas is visible on page load as a default.
and here is an error in the console when loading the screen i reference in the video from screen 1
I just tested your Issue 2 using StP UI and it seems the same. I placed a button to show the computed height and width on the canvas but I get ZEROS all the time.