Seems like a reasonable change to be honest. A registered Democrat changed his registration to Republican and filed as a Republican in order to siphon away Republican votes. This would prevent him from running as a Republican on the basis that he was a registered Democrat within 90 days of filing, not for any other reason.

It doesn't make "one of two R's run as unaffiliated", it makes the Democrat who's ran as an R appear as unaffiliated.

I'm sure if a GOP spoiler had entered the ballot as a (D) then that would be viewed as inappropriate here.