Problem in DHCP radius accounting

DHCP Radius account seems to work fine and is very useful, but it has a problem on ‘stop’ record, showing the field ‘Acct-Session-Time’ with value of zero instead of how many seconds the user has received lease for.

As described in RFC2866:

Acct-Session-Time
Description
This attribute indicates how many seconds the user has received
service for, and can only be present in Accounting-Request records
where the Acct-Status-Type is set to Stop.

Mikrotik send Accounting-Request records like this:

rad_recv: Accounting-Request packet from host xxx.xxx.xxx.xxx port 50585, id=150, length=158
	NAS-Port-Type = Ethernet
	NAS-Port = 2208306370
	Calling-Station-Id = "1:0:15:d1:89:25:1f"
	Framed-IP-Address = 172.24.11.214
	Called-Station-Id = "dhcp_mikrotik"
	Agent-Remote-Id = 0x0015d189251d
	Agent-Circuit-Id = 0x20000004
	Event-Timestamp = "Jul 20 2018 13:04:26 ART"
	Acct-Status-Type = Stop
	Acct-Session-Id = "c214a083"
	Acct-Authentic = Local
	Acct-Session-Time = 0				<--- problem
	NAS-Identifier = "Mikrotik"
	Acct-Delay-Time = 0
	NAS-IP-Address = 10.10.0.1

Anyone else has seen this problem?