FRM Level 1: question on Value of Forward, with price immediately change

:slightly_smiling_face: :slightly_smiling_face:As this question shown as example of value of a stock index forward contract:

Question:

The price a 6-month forward contract for which the underlying asset is a stock index with a value of 1,000 and a continuous dividend yield of 1%. Compute the value of a long position of the index increase to 1,050 immediately after the contract is purchase.

the answer given is:

1,050e-0.01*(0.5) -1,015e-0.04*(0.5) =49.75

My question is, why 1,050 only discounted for dividend yields, while 1,015 needs to discounted as RFR and Dividends

Thank you