AutoSSL ends with "global destruction; memory leak" errors

Symptoms

I'm receiving this message after the AutoSSL cron job runs:

The system finished checking 1 user.
Emptying Let’s Encrypt’s DCV (Domain Control Validation) cache …
Freeing DNS::Unbound::QueryContext=SCALAR(0x96bc168) at global destruction; memory leak likely! during global destruction.
Freeing DNS::Unbound::QueryContext=SCALAR(0x98ec9c8) at global destruction; memory leak likely! during global destruction.
Freeing DNS::Unbound::QueryContext=SCALAR(0xae2c0f0) at global destruction; memory leak likely! during global destruction.
Freeing DNS::Unbound::QueryContext=SCALAR(0x8f5bb20) at global destruction; memory leak likely! during global destruction.
Freeing DNS::Unbound::QueryContext=SCALAR(0xa085290) at global destruction; memory leak likely! during global destruction.
Freeing DNS::Unbound::QueryContext=SCALAR(0xa019c50) at global destruction; memory leak likely! during global destruction.
Freeing DNS::Unbound::QueryContext=SCALAR(0x9c0cc10) at global destruction; memory leak likely! during global destruction.
Freeing DNS::Unbound::QueryContext=SCALAR(0x9631700) at global destruction; memory leak likely! during global destruction.
Freeing DNS::Unbound::QueryContext=SCALAR(0x91dcb20) at global destruction; memory leak likely! during global destruction.
Freeing DNS::Unbound::QueryContext=SCALAR(0x9c83260) at global destruction; memory leak likely! during global destruction.
PID 65269 (/usr/local/cpanel/bin/autossl_check): Cpanel::DNS::Unbound::Async=HASH(0x4dbe440) destroyed at global destruct! at /usr/local/cpanel/Cpanel/Destruct/DestroyDetector.pm line 81 during global destruction.

Cause

This issue occurs because AutoSSL DNS queries are canceled before all DNS queries are cleaned up. DNS Unbound returns this message as the result of freeing up the queries at the end of the operation during global destruction.

We've opened an internal case for our development team to investigate this further. For reference, the case number is CPANEL-50714. Follow this article to receive an email notification when a solution is published in the product. 

Resolution

The error can be safely ignored.