For the past few weeks, I've occasionally run into the following scenario:

I'm animating as usual in Spine, when suddenly I notice that pressing Play or scrubbing the timeline results in setting a key for the currently selected bone on every frame that the playhead touches. If I turn off Auto Key (which I have on all the time), this behavior stops. If I turn it back on, it continues. Closing Spine and reopening it fixes the issue for a good long while until it spontaneously recurs.

Maybe this isn't a bug and I'm accidentally regularly hitting some keyboard shortcut for an obscure toggle? Since this occurs across all scene files and two different computers, I'm forced to conclude that it's either an error on my part, or a bug with the editor. I'm unable to provide steps to reproduce, despite my best efforts to simulate clumsy keyboard presses and clicks during playback. If I do figure any more out, I'll update here. In the meantime, if anyone else has experienced this, please chime in!

I'm running 3.5.22 Professional, though I've been having this happen sometimes even before I recently updated from 3.4.02 to this version.
I'm relatively certain that the keys it set were similar to what would happen if I used Key Selected, as it created keys on every frame for most of the items in the dopesheet but not necessarily all of them. I'll analyze the behavior more closely next time I trigger it, and try to be more vigilant about what possible thing I'm doing to get it into the bad state.

At work, I use Spine on a Surface Pro 4 and at home I use a Surface Pro 2, but in both cases I use a boring old USB optic mouse with no fancy smoothing that I know of. Which isn't to say that the root of this problem couldn't lie in some obscure quirk about Surface Pros in general, possibly with my hand grazing the attached keyboard's track pad while hitting hotkeys. I'll give that theory a poke tomorrow morning at the office.

Tested today, but can't seem to get it in a bad state with the trackpad, despite repeated attempts to screw things up by doing weird random gestures during playback, clicking wildly like a madman to try to transform things with all manner of rapidly toggled transform tools while also swiping around on the trackpad. The fact I couldn't explode it while trying to do everything wrong is of course a testament to Spine being a well-built ship. I'll continue to keep an eye out for it to recur naturally!