Arrow keys intermittently doubling

[DrD]

I experimented with this issue by filling the command line with alphabetically ordered text characters. Then about every third key press, arrow left or arrow right, I was noticing this double shift, as well. My testing was with a hardware version C machine, OS V0.048.635.

I was surprised to see this happen consistently, because I hadn't noticed it before, probably due to not using the arrow keys enough to pick up on that quirk. My key press cadence didn't seem to matter. It doesn't 'feel' like key bounce, more like the effect of a key buffer issue. Do the arrow keys happen to be double buffered?

-Dale-

UPDATE:

I selected the "C-F-O On" diagnostics, and then tried some of the key test choices, followed by the option 9 reset. Since then I have NOT had any further problem with the arrow key (left or right). I've tested this in the same way as originally described, several times, over approximately 15 minutes with no further skipping problem.

-Dale-