We have upgraded our system from 8.5 2021-02-13 (build 85360175) to 8.5 2021-04-18 (build 85360449) because older build suddenly stopped send and received emails for no reason (Database was marked as Live in Database status setting)
And now I can see "Updating wrong E-Mail Queue record with Sent Flag" in the email gateway log. Though it looks like all emails in the queue were sent.
Shall we worry about this?

2021-05-10 12:52:12 (1) SYSTEM Sending Email from Virginija
2021-05-10 12:52:12 (1) Updating wrong E-Mail Queue record with Sent Flag
2021-05-10 12:52:13 (1) M4USleep called on main thread: 100

2021-05-10 12:52:13 (-1) /THREAD(10) SMTP failed with code 421: Network error sending: QUIT
2021-05-10 12:52:13 (1) Updating wrong E-Mail Queue record with Sent Flag
2021-05-10 12:52:13 (1) M4USleep called on main thread: 100