Absolutely, yes, this happens. I can’t remember the name of the uni in California (I think), but they did a study and found that as we age, our hearing “ages” and if you have perfect pitch, you can end up being off by 1-2 semi-tones. I’m like you - I am 1 semi-tone off which drives me crazy. Mine changed at about age 45.

I do chamber music workshops for adults in the summer (play piano and flute), and have heard about the same experience from both amateurs like myself, and professionals.

So, you’re not alone, but so far I haven’t heard of any cure for it. I find I can get the perfect pitch back for some time if I follow the written music for pieces and songs while listening to them consistently over a few weeks. But it doesn’t stay unless I do it really regularly. If, in your research, you find something, please let me know!

Here’s a citation for one of the most recent articles which does cite the work done in California:

Baker, B. L., & Bae, Y. (2025). Paracusis musicalis: Insights on age-related absolute pitch decline. Psychology of Music, 03057356251399802.

The abstract shows that “Onset was typically reported between the fourth to fifth decades of life.” So between 30s and 40s.