Problem with VDB (pixelating render)

i got problem sometimes smoke appear pixeleting in render. in this case i have volume with fog and vdb smoke inside and this smoke looking strange when im render it/ chewits
why chewits?

sometimes in render it happen without volume fog
it looks like square holes in smoke

my specs RTX 3090
Ryzen 5950x
128 gb ram

If i had to guess, your density might be too high.