Balance RR

Hi Can any one help I am using RB4011iGS+ and I am using Balance RR my internet connection for Virgin Media I am using 4 Ethernet ports from Modem and then Balance RR and Bridge to SFP port to my UDM Pro and it work but after some time it drops Balancing on RX and drops to one slave but TX still uses all 4 Slaves It is driving me crazy and if any one can point me in right direction. the TX balances perfect but RX not so much.

dec/23/2021 16:04:38 by RouterOS 7.1.1

software id = EADM-A60K

model = RB4011iGS+

serial number = F0280F868726

/interface bridge
add admin-mac=C4:AD:34:BD:B1:39 auto-mac=no comment=defconf name=bridge
add arp=disabled name=vmbridge protocol-mode=none
/interface ethernet
set [ find default-name=sfp-sfpplus1 ] advertise=10000M-full
/interface bonding
add arp=disabled link-monitoring=none name=vmbond slaves=
ether4,ether5,ether6,ether7
/interface list
add comment=defconf name=WAN
add comment=defconf name=LAN
/interface lte apn
set [ find default=yes ] ip-type=ipv4
/interface wireless security-profiles
set [ find default=yes ] supplicant-identity=MikroTik
/ip pool
add name=default-dhcp ranges=192.168.88.10-192.168.88.254
/port
set 0 name=serial0
set 1 name=serial1
/routing bgp template
set default as=65530 disabled=no name=default output.network=bgp-networks
/routing ospf instance
add name=default-v2
/routing ospf area
add disabled=yes instance=default-v2 name=backbone-v2
/interface bridge port
add bridge=bridge comment=defconf ingress-filtering=no interface=ether2
add bridge=bridge comment=defconf ingress-filtering=no interface=ether3
add bridge=bridge comment=defconf ingress-filtering=no interface=ether8
add bridge=bridge ingress-filtering=no interface=ether1
add bridge=vmbridge ingress-filtering=no interface=vmbond
add bridge=vmbridge ingress-filtering=no interface=sfp-sfpplus1
/ip neighbor discovery-settings
set discover-interface-list=LAN
/ip settings
set max-neighbor-entries=8192
/ipv6 settings
set disable-ipv6=yes max-neighbor-entries=8192
/interface list member
add comment=defconf interface=bridge list=LAN
/ip dhcp-client
add interface=bridge
/ip dhcp-server network
add address=192.168.88.0/24 comment=defconf dns-server=192.168.88.1 gateway=
192.168.88.1
/ip dns
set allow-remote-requests=yes
/ip dns static
add address=192.168.88.1 comment=defconf name=router.lan
/ip firewall filter
add action=accept chain=input comment=
"defconf: accept established,related,untracked" connection-state=
established,related,untracked
add action=drop chain=input comment="defconf: drop invalid" connection-state=
invalid
add action=accept chain=input comment="defconf: accept ICMP" protocol=icmp
add action=accept chain=input comment=
"defconf: accept to local loopback (for CAPsMAN)" dst-address=127.0.0.1
add action=drop chain=input comment="defconf: drop all not coming from LAN"
in-interface-list=!LAN
add action=accept chain=forward comment="defconf: accept in ipsec policy"
ipsec-policy=in,ipsec
add action=accept chain=forward comment="defconf: accept out ipsec policy"
ipsec-policy=out,ipsec
add action=fasttrack-connection chain=forward comment="defconf: fasttrack"
connection-state=established,related hw-offload=yes
add action=accept chain=forward comment=
"defconf: accept established,related, untracked" connection-state=
established,related,untracked
add action=drop chain=forward comment="defconf: drop invalid" connection-state=
invalid
add action=drop chain=forward comment="defconf: drop all from WAN not DSTNATed"
connection-nat-state=!dstnat connection-state=new in-interface-list=WAN
/ip firewall nat
add action=masquerade chain=srcnat comment="defconf: masquerade" ipsec-policy=
out,none out-interface-list=WAN
/system clock
set time-zone-name=Europe/London
/system resource irq rps
set sfp-sfpplus1 disabled=no
/tool mac-server
set allowed-interface-list=LAN
/tool mac-server mac-winbox
set allowed-interface-list=LAN

For bonding, the traffic distribution is only done in Tx direction. The two peers do not mutually coordinate the strategies or ask each other for permission per packet - there are only mechanisms to monitor the transparency of the individual links and eventually stop using them completely.

So if by Tx you mean the Mikrotik → VM modem direction, and by Rx you mean the VM modem → Mikrotik direction, you have to look for the issue at the modem side.