Poor methylation (MTHFR) is often associated with high serum B6 as it's in the same metabolic pathway - and it could be building up as it's not getting into cells where it's needed. Something similar happens with B12. Resolution is a matter of getting more methyl donors (e.g., choline, betaine) in your diet or a Rx for pyridoxal 5’ phosphate (PHP) supplement (MTHFR-safe version of B6).

Not a medical person, just a below average methylator who's been digging into this.

If you've already gotten a DNA report from 23&me or ancestry.com, there's a free online tool that takes your raw DNA and returns a methylation report

https://chrismasterjohnphd.com/tools/2019/07/27/much-choline-eat-genetic-calculator/

Hoping this helps someone...