what do these logs mean in mail.log?

Nov 18 10:23:03 mx dovecot: auth: Warning: Event 0x560045857eb0 leaked (parent=(nil)): auth-client-connection.c:338 Nov 18 10:23:03 mx dovecot: auth: Warning: Event 0x560045894390 leaked (parent=(nil)): auth-client-connection.c:338 Nov 18 10:23:03 mx dovecot: auth: Warning: Event 0x56004589d3e0 leaked (parent=(nil)): auth-client-connection.c:338 Nov 18 10:23:03 mx dovecot: auth: Warning: Event 0x56004588f810 leaked (parent=(nil)): auth-client-connection.c:338 Nov 18 10:23:03 mx dovecot: auth: Warning: Event 0x560045857240 leaked (parent=(nil)): auth-client-connection.c:338 Nov 18 10:23:03 mx dovecot: auth: Warning: Event 0x56004589cfd0 leaked (parent=(nil)): auth-client-connection.c:338 Nov 18 10:23:03 mx dovecot: auth: Warning: Event 0x56004586b130 leaked (parent=(nil)): auth-client-connection.c:338

I am using this version dovecot in a ubunto 20.04 box.

# dovecot --version 2.3.7.2 (3c910f64b)

thanks.