Blocky and pixelated Heterogeneous Volumes In 5.3 runtime

hello,

I’m working on a flying STG game involves Heterogeneous Volumes clouds, and got this weird rendering issue. The clouds looking all right in editor:

but becomes this “pixel sorted” look when play:


in addition, this issue doesn’t happen regularly, but much more frequently in specific level (while the clouds setting, materials are all exactly same)

Here is my material setup, nothing fancy I think

I also checked related concole commands, they all have default values. Tried different sampling, shading, etc. but nothing changed.

Any clue? would be much appreciated!