@jzchen I messed around with it this morning before kicking of my day. Having the complete opposite results as you with the Deco x55 Pro. Rebooted once, it retained WAN addresses, rebooted a second time, pulled LAN address, rebooted two more times, kept WAN, yanked power from Deco x55 Pro, still kept LAN. Changed out the CAT6 cable, retained LAN. Went into Deco x55 Pro Internet Connection option and changed to PPPOE and Saved, and then back to Dynamic, then got the WAN address.

Never touched the BGW320. I might put a dumb switch between the Deco and the BGW320.

  @JDThreeee 

OK, I unplugged my Deco, plugged in a spare Windows 11 24H2 Laptop I have with a different ethernet cable directly to the BGW320 (passthrough is set to DHCPS-dynamic and that is only thing connected - WiFi is disabled). Initially it got the WAN address (107.) as expected, I rebooted, IPConfig /release - /renew a couple times, kept WAN address. I then disabled the NIC by simply right-clicking on "Ethernet 2" and selecting "Disable" and the re-enabling by right-clicking and choosing "Enable", second time I did this, I recieved a local LAN address. Did it again and recieved the WAN address.

So it appears this is a problem with the BGW320 and not TP-Link given my Windows laptop is doing exactly the samething

  @Ocvl Thought about doing that but really didn't want to have to deal with AT&T changing the WAN IP Address, though not sure how often they do that.