Glitchy autoplaback of moves for online games in FF browser

Okay, it may be a trifle and of totally no importance to others, but here's the thing. I've been playing a lot of correspondence/online chess on the site recently. Obviously, playing such games, you feel the need to review the earlier moves from time to time, especially in the early part of the game, to get the idea of what was going on, what the "flow" of the game was.

And I know that most people would just click through the moves, but my hands are affected by a neurological condition, so making repetitive clicks is a little uncomfortable for me. But, hey, there's the autoplay button, right? Right...

And here's the problem: the autoplay is glitchy. Well, at least, it doesn't work well in my browser (the latest Firefox). It seemingly works pretty normal, but every third or fourth move it would "stammer" -- tarry on a white's or a black's move, and then sputter out two subsequent moves immediately, skipping the animation. I'm not after the animation, of course. What I would like to see is the moves played back in fairly regular intervals, just as it was, to all appearances, originally designed to happen. Ideally, I'd also like to have a control in the settings for regulating the autoplay speed -- as for my taste, it could be a bit lower.

Thank you to anyone who takes interest in this little technical issue of mine.