x-tag is not working

[simotuki11]

The following is about the verification process.

Even if the x-tag value in the AMS header is expired, the verification result will be "pass".

When sealing the ARC, we set the x-tag to a date that was earlier than the t-tag and sent the email.
The verification on the receiving side resulted in a pass.
We expected the result to be fail, because the validation time had expired.