My character’s blendshape animations are not being exported!

I'm working on the development of a game in Unity, and the characters have facial animations using blendshapes. I used to be able to export them without any issues, but now, for some reason, they come in without keyframes — they’re only baked.

These are the export settings I’m using, the same ones I’ve always used and that used to work fine. I already tried reverting to version 4.2 LTS, but it didn’t solve the problem.

Here I show the blendshapes, which are controlled by drivers using 3 bones:

Here you can see the keyframes on the bones that drive the blendshapes:

And finally, here’s how the blendshape keyframes appear in Unity:

Important note: The export settings are the same as always. I’ve been exporting this way for years.