@loadii 

it could be both of them doing it from what I just read.

What the symptoms point to

• Deco is sending malformed responses to legitimate Alexa mDNS queries. That's not normal. The packet is probably failing DNS message format checks (wrong compression pointers, bad name labels, length issues, etc.).
• Alexa retries → loop → storm, especially with 7 devices. This matches known bad behavior where one side keeps hammering because it never gets a usable answer (or even a clean error).
• It doesn't happen with your Asus AX86U on another VLAN. That strongly implicates the Deco's mDNS responder/proxy/IGMP snooping/forwarding logic.

TP-Link Deco systems have a history of mDNS quirks:

• Problems propagating multicast/mDNS properly between nodes or across VLANs.
• Occasional malformed packets reported in packet captures (e.g., when reflecting or proxying advertisements).
• General multicast handling can be finicky in mesh/router mode compared to more full-featured routers like Asus.

Amazon Echo devices aren't perfect either — there are past cases of buggy Echo firmware causing mDNS floods — but the fact that it only happens against the Deco (and not the Asus) points to the Deco generating bad replies that trigger Alexa's retry logic.

Likely root cause

The Deco is probably running some kind of mDNS proxy/reflector (common in mesh systems to make discovery work across nodes) that's buggy. It sees the Alexa query, tries to respond or forward, but mangles the packet. Alexa treats it as garbage → retries immediately → storm.This is not how proper mDNS should work. Compliant responders should send valid packets or nothing. Clients should have backoff (and most do), but aggressive retry on total garbage is a known weak spot in some IoT implementations.

This is a common pain point with consumer mesh systems — they often cut corners on multicast/mDNS to make the "it just works" marketing, but edge cases like this expose it.

  @JimmyHerbert 

Hi All,
If you experience abnormal phenomena, such as network instability or device disconnections, after upgrading the Deco BE63 V2 firmware to v1.3.2, we suggest trying the tips below and providing more details about the disconnection. This will help us identify and resolve the issue. Thank you for your cooperation.

1. Please go to the Deco app > More > QoS page and check if the QoS feature is enabled. If so, please turn it off and check if that helps.

2. Please describe the phenomenon you are experiencing, and share details about the disconnection so we can further analyze the issue:
    1) Please describe your network topology, or go to the Deco app > Network tab, tap on a Deco unit, and send us screenshots of the "Show Map" and "Show List" pages. 
    2) Who is your ISP? What is the "Internet Connection Type" listed under Deco app > More > Internet Connection? 
    3) What is the LED status on the main Deco and satellite Deco units when the issue occurs?
    4) How many devices are connected to the Deco network? When the issue occurs, do devices stay on Wi‑Fi but lose internet, or do they disconnect from Wi‑Fi? Do all devices experience the issue simultaneously? 
    5) How do you restore the connection? For example, does rebooting the Deco nodes temporarily restore the connection? 
    6) Please let us know if you have any special settings enabled, such as Parental Controls, VPN, etc.

Best Regards