2003 Accord 4-door sedan, I4, AT

I changed my air filter at 26,400 miles (last Tuesday). Didn't notice if
the "Maint Reqd" light came on that day, but starting the next day the
MR light blinks 10 times whenever I start the car. Nothing in the Owners
Manual explains why it's coming on at 26,000 miles. Is it possible to
cause this when changing the air filter?

FYI, changed the cabin pollen/dust filter a couple of weeks ago - I was
amazed at how crummy it was! Will change it annually from now on.