Reproducing on v0.6.19_pre3 of the Blockbench plugin

The color filter keyframes are not exported, at all. No matter what animation type, looping mode, duration, or number of keyframes used.

The reason why may have something to do with the Color Filter toggle not being enabled for the affected parts:

Enabling this toggle after exporting does not "restore" these keyframes. They are lost, as if not being read at all.