Sorry, I meant naked-shorts by MMs. Any idea?
For your example I believe you are correct; According to Nordnet it is the shorter who needs to pay the dividend to the person who lended out the shares, but it does not say anything about share-dividends... Which might be a tricky (and rare) situation, especially for SIAF/TRW where the dividend-shares aren't on a market (and I assume the compensation has to be done before the "TRW-trade-platform" is up and running)
Nordnet doesn't say anything about when, but I would guess that the shorter will have to pay on or around the payment-date, i.e in two batches for SIAF/TRW. Although for SIAF/TRW it might be "tricky", i.e one might need to remind your broker about it if you have lended out SIAF-shares.