I don't see how sticky keys could cause what I'm experiencing. I get the behavior in sessions where only mouse clicks have been used, from desktop to the page where I have the problem.
Nonetheless, I've cleaned my mouse (actually, trackball), and will buy a can of compressed air.
There is nothing (ledger, etc.) impinging on the keyboard.
I called my knowledgeable computer guy and described the problem. He's as stumped as I. Incidentally, he discounted the keyboard stick, just as I did and do.
He pointed out that usually if it's a board going bad, or something like that, he would expect it to throw me off the web, or shut down the computer entirely, rather than reverting to a previous page but allowing return by the right arrow.