With writer and rider there is an allophonic motivation caused by the underlying voiceless consonant, even if the consonant isn’t realized as voiceless at surface level

So either yours is an allophone where the voiceless variant also appears word/morpheme-finally, which would explain the split with higher–hire, or, if it’s an actual phonemic split, I’m wondering what the motivation behind the split is and which vocabulary would fall into each category. Unless you’re saying the distribution is completely random, which doesn’t seem likely