FBX exported from maya lost some blendshapes when import to UE4

Development Character & Animation
1

The FBX contains about 200 blendshapes and when imported to UE4 about 20 blendshapes could not be found in morphtargets. And everytime imported lost the same 20 blendshape.

I had tested in 4.23 and 4.24 and got the same result. Also had tested in Unity and there was no problem.

Is there some requirement for the blendshapes imported to UE4？

2

Maybe it has to to with the names of the shape?
Perhaps a name lenght value (too long of a name on the shape?)

Out of principle. Try to rename one that works to the same name as one that does not work, and check if the import works or what it does.