Problem Description
Changing the animation speed every tick (like matching animation speed to sprite's movement speed) breaks a looping animation that has been set to ping pong.  Instead of smoothly changing the animation speed it stops using all the frames and only uses 2 frames.
This only occurs with ping pong selected.  If you loop without ping pong it works ok.
    
Attach a Capx
https://dl.dropboxusercontent.com/u/358 ... speed.capx
    
Description of Capx
Watch the flapping animation.  Click "fluctuating speed" to set the animation based on a sine.  Click "Static Speed" to set the animation speed to a set number.
Steps to Reproduce Bug
    -  Create Animation that loops and ping pongs
    
-  Change animation speed per tick
    
-  breaks!
Observed Result
The animation loops using only a couple of frames rather than the whole set.
    
Expected Result
It should smoothly change the animation speed without breaking the animation's flow and should use all the frames instead of a couple.
    
Affected Browsers
    -  Chrome: (YES)
    
-  Node: (YES)
Operating System and Service Pack
Windows 10
    
Construct 2 Version ID
R221 64 bit Steam