I all - new to the forums long time Microtik user.

We have a RB4011iGS that we use as a the primary Router for our network
Ethernet 1 is setup as the WAN port and the Ethernet 2-8 are bridged as the LAN
A pppoe connection is attached to Ether 1

Internet works fine as does the bridge.

My ISP called me today to ask if we could disable DHCP on the WAN connection - they stated the unit was connecting via PPPoE and then doing a DHCP request and holding that as well.
I checked and I had the DHCP-client disabled on that interface so I deleted it (even tho it was disabled)

The ISP reported the device was still sending DHCP requests - quoting ethernet1's MAC address as the iniator. They also gave me the IP address they assigned via PPPoE and DHCP
Only the PPPoE obtained IP responds to ping.

What am I missing

Details
RouterBOARD
Model RB4011iGS+xxxxxxxx
Firmware Type al2
Factory Firmware 6.44.4
Current Firmware 6.49.7
Upgrade Firmware 6.49.7

Free Memory 967.8 MiB
Total Memory 1024.0 MiB
CPU ARMv7
CPU Count 4
CPU Frequency 1400 MHz
CPU Load 0 %
Free HDD Space 423.0 MiB
Total HDD Size 512.3 MiB
Architecture Name arm
Board Name RB4011iGS
Version 6.49.7 (stable)
Build Time Oct/11/2022 14:37:24
Factory Software 6.44.3

Did you try a reboot after deleting it?

Yes was the first thing we tried after deleting.. Although it was a UI reboot which I assume is pretty much the same as turning off the switch.

Can be one your internal device that send DHCP request outside the device, like TP-Link Repeaters or TP-Link PowerLine.

If the ISP have something configured wrong (LIKE DHCP SERVER ON PPPOE CLIENT....) it may appear that the packet is coming to you...

1) Disable Detect Internet (on Interface, button "Detect Internet" set all to NONE) [88%]
2) Disable DHCP Server Alerts (on IP / DHCP Server / Alerts delete all) [2%]
3) Check and remove all DHCP Clients (on IP / DHCP Clients delete all) [10%]