What is "unreasonably far in the past"?

[Macke]

Suggest a re-word of this sentence to say something clearer... perhaps...
"The iat (issued at) claim MUST specify the time at which the Client Attestation PoP was issued. Note that the authorization server may reject JWTs with an "iat" claim value that is deemed to increase risk of mis-use to a level they choose."

Line 225 of current editors .md

[tplooker]

This language was inspired by RFC7523 which is somewhat related to this draft.

The JWT MAY contain an "iat" (issued at) claim that identifies
the time at which the JWT was issued. Note that the
authorization server may reject JWTs with an "iat" claim value
that is unreasonably far in the past.

Your suggested text is more general but it doesn't really indicate the driver for deciding the risk which is the time represented by the iat value relative to the time of validation, which is what the current text focuses more on.