[Remind-Fans] Getting a "+60" reminder 63 days out?

[Tim Chase]

G'morning,

I have a reminder to shop for a TV for a Christmas gift for our
family:

  REM Dec 25 2019 +60 MSG %"Start shopping for TV replacement%" due %b%

No OMIT, nor anything fancy that (AFAICT) should slide that around.
And in fact, if I simply use that one line as my reminder file, I
don't get a reminder today.

However, when I include the standard "globals.rem" file

  $ remind <(cat globals.rem; grep TV tim.rem)

I started receiving notifications today (2019-10-23), 63 days out:

  Reminders for Wednesday, 23rd October, 2019 (today):

  Start shopping for TV replacement due in 63 days' time

It's not a *problem* (the 60 days was really just a rough "don't
forget to start watching sales" reminder), I was just a bit confused
and hoped for a better understanding of what would extend that "+60"
to notify me more than 60 days out.

Thanks for any insights,

-tim