4.6.0-op24 open source drivers firmware request

Can you or someone else explain what the "certain performance and compatibility issues with the open-source drivers for the model" are?

I had to switch to the 4.6.6 OP24 version due to ExFat network storage issues (see Flint 2 ExFat network storage) and haven't noticed any issues with it so far. Curious. Thank you.