actions don't seem to record layer visibility

[BA]

so i'm recording lots of actions at the moment, and many of them involve switching the visibility of certain layers on and off.

at first i thought i was going crazy, but now i've confirmed that it's not all in my head - i've recorded keyframes within the actions to turn off layer visibility, and yet, when i copy the action into the main timeline, those keyframes don't show up!

then i go into the action to double-check, and surprise, the visibility keyframe is no longer there.

the weird thing is, it seems to only happen with 'visibility OFF' frames... ie, the frames that tell visibility to switch ON remain... but the OFF frames tend to vanish, no matter how many times i record them into the action.

what's going on???