Character's eyelids not keying properly


Hi, dear fellows!

I’m having strange things going on when I try to animate eye blinking. When I key the eye controller value, it first acts like it was keyed. But it wasn’t actually! If I come back to this same frame and re-enter the value once again, it looks ok again. But now when I switch to any other frame it keeps the value like ‘frozen’ from the previous tricky frame. And if I correct this with a proper value, it then freezes with this current value here and there and everywhere.

I made a short screencast to illustrate what I mean. I have no idea what’s the issue here. The rig isn’t mine, I just use it for further animations. I’m not strong at rigging but could it be it has something to do with the rig/skin of the character? Or is it some glitch maybe?

I also attach the file with the character so you can have a look and maybe save me! :see_no_evil::see_no_evil::see_no_evil: Any help, advice or guesses are truly welcomed! Thank you in advance, guys.

Dropbox link to the file: