Hello,
Just tested the v1.7 no save version and I'm still getting the same glitchy screen, now black then white.
Note: I deleted the save file created by the original v1.7 to avoid any conflict or issue.
And to answer your questions:
1. The glitchy screen used to appear only after pressing button A once Stage 1 started. Now with v1.7 no save test version, the glitchy screen appears right away when Stage 1 starts and without pressing any button.
2. I didn't try v1.6 or any other version before 1.7.