Those don’t eliminate the spoiler effect, but it does end up looking different. (Maybe has a different name in this form?)

My blue state has a blanket primary, and this last election I saw that demonstrated:

One race had two Republicans and like half a dozen Democrats and another half a dozen in other parties. The Republican vote of course was split between the two candidates. The Democrat vote was split like a hydra and we very nearly had (few hundred votes away) the two Republicans go to the general!

Fortunately, the top Dem barely squeaked into second place, and then easily won the general, but it was mighty close.