It's 2048; in other words, it's 2 valid shares at diff 1024 diff, which would result in 2048 difficulty units or work units. it's up to the pool code and database whether they store just 1 column that says "difficulty units," which in this is going to be 2048, or assign a different row for every share and store difficulty in another column, or override the same exact cell every time your miner submits a share, but all of that is irrelevant; by the end of the day, you are getting rewards based on the number of shares you submitted at x difficulty, which is the total difficulty units you contributed in that round or period.

Obviously, this is not related to the Bitcoin protocol or consensus; any pool can still reward you for "over-delivering," which in your case would be 4,083.3 work units, but I am not aware of any pool that does that.