@Santa1701 I downgraded back to version 15 and the problem went away. Below is a link for V1.0.15 https://static.tp-link.com/upload/firmware/2024/202402/20240218/Deco%20BE85_V1_1.0.15_240117.zip

@David-TP thank you, email received. ISP provider is TPG, the BE85 is directly connected to the NBN box. my old router was AX5400 Dual-Band Gigabit Wi-Fi 6 Router. thanks

@Timb000 no I haven't turned on QoS, I have reset the router to factory default as I thought maybe that will work but with no luck

@David-TP I've tried every single port even put in a SFP and tried that but none of them made a difference. The original port was the 10Gbps rj45, I've spoken to the ISP to see if it was on their...

@Alexandre. Thanks for that however I did both of the suggestions with no luck

After recent firmware update I'm getting abnormal WAN port speed and it dropped down my speed from 936 to 86mbps