When "frametime" is used for an animation in a resource pack, it will be ignored if the argument (or whatever you call it) "time" is set to 1. For example: I set "frametime" to 3, but I have a frame that I want to be 1 tick long. So I add "time": 1.
What I expected to happen: all frames except the one I set to 1 tick long would be 3 ticks long.
What actually happened: All frames were the default 1 tick instead of the correct 3 ticks.
I will include a screenshot of my mcmeta. If you use it (with a 3 frame animation), all frames will be 1 tick long.
I'm not %100 sure if my explanation (as stated in the title) is correct, but it was the only way that I could explain it.
Edit: Added an example resource pack and updated the screenshot in the attachments. Place a piece if dirt and watch how all the frames are 1 tick long. WARNING: may be seizure inducing
Edit 2: Oops turns out this has been fixed. Edited accordingly. It's the converter that is not converting timing files correctly.