Fix a bug/feature of a Mikrotik router?

Question

Computer networks

Good day!
There is a problem with the Mikrotik router and the jiayu g4s phone - they don’t want to make friends over wifi, in which device I don’t know the problem, the essence of the problem:
there is a RouterBoard 951Ui-2HnD, a beech and 3 android devices cling to it via wifi, the problem is only with one device - G4S , I would sin on him, if not for one circumstance - with other access points, all devices worked fine, and therefore I think that somewhere there is a tricky setting that does not let one phone on android kitkat into the Internet, on others an older android .
The essence of the problem:
After the Lease time, the route to the external network disappears .
I connect the bodies to wifi, wifi works, the Internet works, everything is ok. After the Lease time expires, a message appears in the log stating that the address is deassigned, after 30 seconds the address is assigned again and then the Internet falls off (only on G4s, everything is ok on other devices). In principle, I could increase the lease time, but I would like to understand the problem. When the Internet fell off - the local network works, I connect via IP to the FTP server on the LAN, to the tick's admin - everything is OK. It does not let it into the outside (by IP too). Once again, I note - everything is ok with other APs
UPD:

Настроил обновление каждые 5 минут,
Реквесты от тела с инетом:
21:58:12 
22:03:01 
22:07:50 

Реквесты от тела без инета (G4s):
21:58:18
22:03:08
22:03:09
22:07:57
22:10:27
22:12:53

Кусок DHCP лога, тело с инетом:
22:31:46 dhcp,debug,packet debug: default received request with id 4177922429 from 192.168.88.195 
22:31:46 dhcp,debug,packet debug:     secs = 289 
22:31:46 dhcp,debug,packet debug:     ciaddr = 192.168.88.195
22:31:46 dhcp,debug,packet debug:     chaddr = 00:08:**:5E:CA 
22:31:46 dhcp,debug,packet debug:     Msg-Type = request 
22:31:46 dhcp,debug,packet debug:     Max-DHCP-Message-Size = 1500 
22:31:46 dhcp,debug,packet debug:     Class-Id = "dhcpcd-5.5.6" 
22:31:46 dhcp,debug,packet debug:     Host-Name = "android-71ef06bd6df5ce2c" 
22:31:46 dhcp,debug,packet debug:     Parameter-List = Subnet-Mask,Static-Route,Router,Domain-Server,Domain-Name,Broadcast-Address,Address-Time,Renewal-Time,Rebinding-Time 
22:31:46 dhcp,debug,packet debug: default sending ack with id 4177922429 to 192.168.88.195 
22:31:46 dhcp,debug,packet debug:     ciaddr = 192.168.88.195 
22:31:46 dhcp,debug,packet debug:     yiaddr = 192.168.88.195 
22:31:46 dhcp,debug,packet debug:     siaddr = 192.168.88.1 
22:31:46 dhcp,debug,packet debug:     chaddr = 00:08:**:5E:CA 
22:31:46 dhcp,debug,packet debug:     Msg-Type = ack 
22:31:46 dhcp,debug,packet debug:     Server-Id = 192.168.88.1 
22:31:46 dhcp,debug,packet debug:     Address-Time = 600 
22:31:46 dhcp,debug,packet debug:     Subnet-Mask = 255.255.255.0 
22:31:46 dhcp,debug,packet debug:     Router = 192.168.88.1 
22:31:46 dhcp,debug,packet debug:     Domain-Server = 192.168.88.1 

Кусок DHCP лога, тело без инета:
22:32:15 dhcp,debug,packet debug: default received request with id 4074859666 from 0.0.0.0 
22:32:15 dhcp,debug,packet debug:     secs = 70 
22:32:15 dhcp,debug,packet debug:     ciaddr = 0.0.0.0 
22:32:15 dhcp,debug,packet debug:     chaddr = 00:08:**:5B:10 
22:32:15 dhcp,debug,packet debug:     Msg-Type = request 
22:32:15 dhcp,debug,packet debug:     Address-Request = 192.168.88.31 
22:32:15 dhcp,debug,packet debug:     Server-Id = 192.168.88.1 
22:32:15 dhcp,debug,packet debug:     Max-DHCP-Message-Size = 1500 
22:32:15 dhcp,debug,packet debug:     Class-Id = "dhcpcd-5.5.6" 
22:32:15 dhcp,debug,packet debug:     Host-Name = "android-335decb29daddc7e" 
22:32:15 dhcp,debug,packet debug:     Parameter-List = Subnet-Mask,Static-Route,Router,Domain-Server,Domain-Name,Broadcast-Address,Address-Time,Renewal-Time,Rebinding-Time 
22:32:15 dhcp,debug,packet debug: default sending ack with id 4074859666 to 192.168.88.31 
22:32:15 dhcp,debug,packet debug:    ciaddr = 0.0.0.0
22:32:15 dhcp,debug,packet debug:     yiaddr = 192.168.88.31 
22:32:15 dhcp,debug,packet debug:     siaddr = 192.168.88.1 
22:32:15 dhcp,debug,packet debug:     chaddr = 00:08:**:5B:10 
22:32:15 dhcp,debug,packet debug:     Msg-Type = ack 
22:32:15 dhcp,debug,packet debug:     Server-Id = 192.168.88.1 
22:32:15 dhcp,debug,packet debug:     Address-Time = 311 
22:32:15 dhcp,debug,packet debug:     Subnet-Mask = 255.255.255.0 
22:32:15 dhcp,debug,packet debug:     Router = 192.168.88.1 
22:32:15 dhcp,debug,packet debug:     Domain-Server = 192.168.88.1

Answer 1

Studies have shown that this is a phone bug, not a router

Answer 2

Try to fix the poppy with an ip address.