Stuttering player animation loop

I'm working on developing a platform game, but I'm having trouble syncing the sprite animation triggers with the player's actions.

For now, I have it so that running and standing, facing left and right, are mostly working. The only problem is that the running animation keeps freezing after each completed cycle. This faulty behavior is unique to running though; the standing animation plays through just fine without pauses.

Since I haven't actually started working on art/sprites, I'm temporarily using Metroid Zero Mission sprites as a placeholder so I can at least see that the right animations are being called at the right time and are looping smoothly.

I'm hoping someone with a little more experience can find where my mistake(s) are.

My event sheet is pretty thoroughly commented, so hopefully it's not hard to understand. The controls are currently [A] left, [D] right, jump.

https://www.dropbox.com/s/hj9wblc326ke9mx/Platform%20Engine%20v0.20140220.capx

A funny gotcha here - go into the run-left / run-right animations for Samus and have a look at the Frame Properties:Frame Speed for animation frame 9. You have it set to 24 - which means it will delay 24 ticks before progressing.

Whoops. It seems I accidentally changed the value for frame speed while intending to tweak the animation speed. I didn't even know there was a separate frame speed property until just now. Thanks!