This is 1965, so expected.
As part of replacing silver coins with clad,
So where Philly minted 929m and Denver 1.36B in 1964, they minted 1.65B in 1965. Those #s are a little deceptive, since 1964-dated silver dimes continued to be minted into 1965, and the clad coinage started after the legislation was approved in late July (so less than half a year).
pg 16

pg47

See:
FY1965 (ended June 1965) with 1964 production data:
https://nnp.wustl.edu/library/book/514150FY1966 (ended June 1966) with 1965 production data:
https://archive.org/details/annualr...967unit_k0d9
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