Learn English – Isn’t “rural” redundant in “rural village”

But, and this is A big "but" here, all of this can be purchased out on the black market.

There could be more than one "but", either earlier in conversation or later.

But, and this is THE big "but" here, all of this can be purchased out on the black market.

There isn't going to be any bigger "but" than this one in this sentence.

To me, there is a subtle difference in meaning here:

You are multi-tasked woman.

This states that the woman often/always has multiple tasks simultaneously assigned to her for completion, whether or not she is capable of doing so, whereas:

You are multitasking woman.

is a statement that the woman in question is currently in the act of completing multiple tasks at once, which carries some implication that she is capable of doing so. Furthermore, this may have been intended as:

You are [a] multitasking woman.

which would imply to me that the woman in question is seen to have some tangible capability to handle multiple tasks at once.