Only first 127 morph targets affect appearance of my model

I’ve cloned UE4 from official GitHub page https://github.com/EpicGames/UnrealEngine and compiled it successfully on my Xubuntu 18.04.

I have a FBX file exported from DAZ Studio 4.10.
The model contains about 230 morph targets.
I’ve imported the file into UE4 and got the following warnings
(don’t think it’s related, but still)

Warning skeletal mesh influence count of 13 exceeds max count of 8. Influence truncation will occur. Maximum Ignored Weight 0.029 
No smoothing group information was found in this FBX scene.  Please make sure to enable the 'Export Smoothing Groups' option in the FBX Exporter plug-in before exporting the file.  Even for tools that don't support smoothing groups, the FBX Exporter will generate appropriate smoothing data at export-time so that correct vertex normals can be inferred while importing. 

I open Mesh View -> Morph Target Preview and change weights of the morph targets.
They affect my mesh visually,
but when it comes to 128th morph target,
I cannot see the difference between 0 weight and 5 — looks like they don’t work,
but any morphs from the first to 127th worked fine.
Nevertheless, I can change any coefficient using FBX SDK in an application written by me,
so the morphs really exist and should affect appearance of the mesh.

How to fix the issue?

Workaround is to go to Edit > Project Settings > Rendering > Optimizations and turn off Use GPU for computing morph targets. You can find this instruction in MorphTargetPreviewer documentation.

Also, it’s said that the bug should be fixed in Unreal Engine 4.21 (4.21.2-release works for me).