Has Sharesight calculated my dividend's foreign source income correctly?

I recently received my first dividend from the ASX:IVV S&P 500 ETF. In the Components of Distributions announcement it says that the Foreign Sourced Income is 99.9998% of the cash distribution.

I have a Sharesight account for tracking dividends, and am confused by how it broke down this dividend. Rather than putting 100% into Foreign Source Income, it put only 1%.

Who’s at fault here: my understanding, or Sharesight? It’s definitely possible that Sharesight has imported the wrong data, but that would surprise me as it is, you know, its One Job.

Also, should I be tracking the "Foreign withholding tax gross-up" portion of the dividend? Is that what the bottom option here refers to?