Returning to frequent travel after several years off & trying to get back up to speed. Thanks the everyone here for all the help.

Currently waiting for UA3375, ORD-GRR, which shows as "delayed - awaiting inbound aircraft." The plane, however is at the gate. United.com shows that we were waiting for an aircraft from SGF that arrived 45 minutes ago, 5 minutes late to the gate.

What gives?