It’s an engine “feature” that has been with the engine since always.
I doubt there is any fix to it other than removing mips and loosing performance.
The mips are updated at runtime. It starts with your lowest and loads in the more detailed ones as memory becomes avaliable/loaded.
Essentially, its a core engine failiure due to some ancient rendring pipeline choiches.
Would love to see a fix.
But fixing your mips, or using a different engine is also a fix 