Interpolate feature doesn't occur at all on textures with "frametime": 1

The interpolate feature allows for each frame of animation on textures to be blended together, allowing them to animate more smoothly. However, it doesn't happen at all if the texture has a frametime of 1, limiting it to 20 fps. This may not be known, as the stone cutter has a frametime of 1, but also disables interpolation manually.

For example, this will interpolate correctly:
"animation": { "interpolate": true, "frametime": 10 }

However, this will not interpolate at all:
"animation": { "interpolate": true, "frametime": 1 }

And this too also won't work:
"animation": { "interpolate": true }
As the default frametime is 1

This only seems to affect "frametime": 1 and no other speed setting. Changing the mcmeta file of the stone cutter to "interpolate": true is the easiest way to reproduce this; you will notice it still stutters through frames, instead of fading to the next frame. The texture or block itself also doesn't seem to matter, only if the frametime is 1.