There have been some similar bugs, but this one’s entirely about using the arrow keys to scroll.
While using arrow keys in the script editor to move around your code after clicking anywhere near the edge of the window and letting it scroll automatically by pressing the right or left arrow key,
as you scroll upwards or downwards by holding the up or down arrow keys immediately after that (without further clicking anywhere and not using the right or left arrow keys after it automatically scrolls) the screen flickers temporarily because the cursor moves to the end of the screen quickly, this is noticeable when you’ve got a lot of nested code or code in one line.
This demonstrates:
^ a script with random code
The cursor doesn’t move through your code, but rather moves towards the end really quick causing a flicker and buggy scrolling.
Scrolling using the scrollbar or scrolling after clicking anywhere causes this not to happen, and the cursor then moves through the code.
The date this bug started occurring is not known and occurs only in the Studio script-editor.