MTA-STS policy expiration date

Hello

I've seen "MTA-STS failure for gmail.com: STARTTLS not supported" here
on the Forum couple of days ago, took a little closer look at MTA-STS
and decided to try to implement it for my domains. Took me couple of
hours, but in the end, not too complicated.

 From MTA-STS DNS Cache File I can see that very few of the domains my
users correspond with have MTA-STS verification setup and of those only
gmail.com has policy set to "enforce". All of the other (including
mdaemon.com) are in "testing" phase.

I've noticed one odd thing. Gmail record in my MTA-STS DNS Cache File
file is:
gmail.com = v=STSv1; id=20190429T010101; expires 2059-11-05T20:47:37Z

In Gmail's policy file, max_age parameter is set to 84600 secs (1 day).
How come MDaemon says record expires on 2059?


Regards