Narrative:

I cleared aircraft X to cross zzzzz at FL340. I handed the aircraft off to adjacent center and subsequently noticed the aircraft descending through FL340. I called the other center to notify them of the unassigned descent; and the controller investigated to learn the aircraft was going to FL240.with covid-19 lack of traffic and talking to a supervisor about unrelated things; my focus was not 100%. I don't know if the aircraft read it back wrong to me or not. We've always got to be on guard.

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Original NASA ASRS Text

Title: Center Controller reported being distracted due to COVID-19 issues and did not hear a wrong read back from a crew; which resulted in an altitude deviation.

Narrative: I cleared Aircraft X to cross ZZZZZ at FL340. I handed the aircraft off to adjacent center and subsequently noticed the aircraft descending through FL340. I called the other center to notify them of the unassigned descent; and the Controller investigated to learn the aircraft was going to FL240.With COVID-19 lack of traffic and talking to a Supervisor about unrelated things; my focus was not 100%. I don't know if the aircraft read it back wrong to me or not. We've always got to be on guard.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.