Dual band issue with new router.

TLDR: I’m having trouble getting both 2.4G and 5G to work on my simple setup.

I use HEX E50UG and CAP ac RBcAPGi-5acD2nD.

I plugged the CAP to my eth5 and did the very basic Capsman config.

# 2025-06-04 17:36:00 by RouterOS 7.18.2
# software id = T5C5-70RK
#
# model = E50UG
# serial number = HHG0A6Q41ZH
/caps-man datapath
add bridge=bridge name=datapath1
/caps-man security
add authentication-types=wpa-psk,wpa2-psk encryption="" name=mt_security
/caps-man configuration
add channel.band=2ghz-g/n .skip-dfs-channels=yes country=lithuania datapath=datapath1 installation=indoor mode=ap name=Config_2.4G security=mt_security ssid=MT2
add channel.band=5ghz-a/n/ac .skip-dfs-channels=yes country=lithuania datapath=datapath1 installation=indoor mode=ap name=Config_5G security=mt_security ssid=MT5
/caps-man access-list
add disabled=yes
/caps-man manager
set enabled=yes
/caps-man provisioning
add action=create-dynamic-enabled hw-supported-modes=ac master-configuration=Config_5G name-format=prefix-identity name-prefix=5G
add action=create-dynamic-enabled hw-supported-modes=gn master-configuration=Config_2.4G name-format=prefix-identity name-prefix=2.4G

When I only provision my Config_5G everything works fine. But when I start to provison and the other Config_2.4G my wireless network start falpping and basically crashes.
Please advise with the looped packet or fix for this.

2025-06-04 17:32:27 interface,warning ether5: bridge RX looped packet - MAC 74:4d:28:7d:d8:f1 -> f4:1e:57:9b:ba:51 ETHERTYPE 0x88bc
 2025-06-04 17:32:32 interface,warning ether5: bridge RX looped packet - MAC 74:4d:28:7d:d8:f1 -> f4:1e:57:9b:ba:51 ETHERTYPE 0x88bc
 2025-06-04 17:33:10 caps,info [74:4D:28:7D:D8:F1/12/ac3d,Join,[74:4D:28:7D:D8:EF]] joined, provides radio(s): 74:4D:28:7D:D8:F2,74:4D:28:7D:D8:F1
 2025-06-04 17:33:14 caps,info 5G-CAP2-1: selected channel 5180/20-Ceee/ac/P(23dBm)
 2025-06-04 17:33:16 caps,info 2.4G-CAP2-1: selected channel 2452/20-Ce/gn(20dBm)
 2025-06-04 17:33:19 interface,info 2.4G-CAP2-1 detect LAN
 2025-06-04 17:33:21 interface,warning ether5: bridge RX looped packet - MAC 74:4d:28:7d:d8:f1 -> f4:1e:57:9b:ba:51 ETHERTYPE 0x88bc
 2025-06-04 17:33:28 dhcp,warning defconf offering lease 192.168.88.20 for BA:79:82:D9:87:B3 without success
 2025-06-04 17:34:06 caps,info [74:4D:28:7D:D8:F1/12/5490,Join,[74:4D:28:7D:D8:EF]] joined, provides radio(s): 74:4D:28:7D:D8:F2,74:4D:28:7D:D8:F1
 2025-06-04 17:34:10 caps,info 5G-CAP2-1: selected channel 5180/20-Ceee/ac/P(23dBm)
 2025-06-04 17:34:12 caps,info 2.4G-CAP2-1: selected channel 2452/20-Ce/gn(20dBm)
 2025-06-04 17:34:20 interface,info 2.4G-CAP2-1 detect LAN
 2025-06-04 17:34:21 interface,warning ether5: bridge RX looped packet - MAC 74:4d:28:7d:d8:f1 -> f4:1e:57:9b:ba:51 ETHERTYPE 0x88bc
 2025-06-04 17:34:24 dhcp,warning defconf offering lease 192.168.88.20 for BA:79:82:D9:87:B3 without success
 2025-06-04 17:35:04 caps,info [74:4D:28:7D:D8:F1/12/791b,Join,[74:4D:28:7D:D8:EF]] joined, provides radio(s): 74:4D:28:7D:D8:F2,74:4D:28:7D:D8:F1

Check MAC addresses on cap radios, also check with used MAC addresses on Hex ether itfs and bridge.
They are to be kept unique.

Maybe even best to simply reset that capac device to caps mode.

Thanks. Reset to CAP mode did the trick.