Medium Transport
Air Traffic Control Fully Certified
Air Traffic Control Time Certified In Pos 1 (yrs) 10
Distraction; Confusion; Communication Breakdown; Human-Machine Interface; Training / Qualification; Situational Awareness
Airspace Violation All Types; Deviation / Discrepancy - Procedural FAR; Deviation / Discrepancy - Procedural Published Material / Policy
Air Traffic Control Provided Assistance; Air Traffic Control Issued New Clearance
Human Factors; Procedure; Staffing
I was training my trainee at Sector X only.  We had all of the airspace combined as well due to COVID traffic (normal).  My trainee pointed out Aircraft Y to Sector Y in ZZZZ center.  They were combined with Sector Z as well.  They approved the point out on Aircraft Y and then started a hand off on an aircraft we did not know about or see yet (Aircraft X).    Neither of us said anything because we did not know what aircraft [in] Sector Y was talking about.   After about 3; 4 seconds of silence from my trainee; Sector Y said 'disregard.'  So we never took the hand off.  A couple minutes later; Aircraft X checked on out of about 160 for FL230.  Sector A airspace was hot FL180 - FL230 with 4 drones delaying.  There was no data block displayed; but we eventually found the limited data block and pulled it up and stole track control and immediately my trainee told Aircraft X to descend and maintain 170 to miss the airspace. Prior to stealing the track; the status of who had track control was listed 'Unknown.'  My trainee said it was OK if he was already above 170; but to descend anyways.  He was climbing really well and got up to about 185 before starting back down.  Aircraft X may have clipped the Sector A airspace for a hit or two while descending.  Safety was never compromised because we had clear radar on all 4 other type aircraft and the closest one was well south of where Aircraft X was 15-20 miles.  I would have intervened if safety was at risk and vectored the aircraft away from danger.Just [need] better coordination and more timely hand off from the north.  Maybe a heads up prior to departure on ZZZZ departures entering our airspace due to proximity to our airspace.
Center Controller reported a hand off issue with adjacent airspace resulting in an airspace violation.