Here is the thing. The tyvek filters will do fine against spores of any sort.
But they will NOT stop hypae.
If, as example, you inadvertently smear a bit of sticky wet grain mucous on the inside of a filter patch and a spore of what have you lands on the outside of that patch- the spore can germinate and send a few hyphae right through the filter.
Of course you can't notice this. You find that your grain is nicely propagated. Maybe 80 percent, and you want to give it one more good shake for even Ness.
Three days later, your bag is gone. Black mold (Never identified it) is the worst.
I figure the mycelium actually forces its way through the filter. Of course those hyphae break up inside the bag and you are done.
Don't let anything on the inside touch the filter. Don't let the filter get wet.