[atomicpossum]

No it probably is a coincidence. Most comic strips are done between 1 and 2 weeks before publication. Some strips run a month out, especially if they're non-topical. Today's technology might allow cartoonist to do their thing minutes before the papers print, but artists still run at artist speed and it's better for the business if every has a buffer zone inbetween what they're working on and what's being printed tomorrow.

This is a Sunday strip. According to King Features guidelines (the last time I saw them), these usually are done about 6-weeks in advance....

[Wacka]

Doesn't he hane a non-topical one in reserve he could substitute in this case?

Why not just not run that one at all. The syndicates have hundreds of strips sitting around waiting for a chance.