I can't honestly say I can recall anybody saying "one" to rhyme with bun. It may be that some have, but I just haven't noticed, but certainly most people I know pronounce it to rhyme with gone.
I'll have to listen more closely, as that's not my perception at all.
Of course, what people say, and what my ears hear aren't necessarily in sync*, particularly as I seem to have the same audio decoding issue that son was diagnosed with.
* In exactly the same way that drivers look but often fail to see