Update: Google has posted a support page for this issue promising a fix tomorrow (1/18). The page says the issue is limited to "People with an Android phone and a Chromecast built-in device (such as a Chromecast or Google Home device) on the same Wi-Fi network" and that a fix will be rolling out via Play Services.

The original story is below.

Users on the Google help forums and Reddit are reporting that Google Home and Google Chromecast devices are causing issues with their Wi-Fi networks. Users say hooking up these Google hardware products leads to an unstable Wi-Fi network or a network that goes down entirely.

The instability was originally thought to affect the TP-Link Archer router series with a single Google device, the Google Home Max. The issue has been slowly creeping out to other devices, though, with the Google Home, Google Home Mini, and Chromecast apparently having similar issues. TP-Link was singled out because it's a popular router brand.

TP-Link issued a beta patch for the Archer C1200, but the company came to the conclusion that the issue isn't with its routers. In a support article, TP-Link writes:

Following initial research and investigation, our engineering team is confident that they've determined one of the key origins of the issue. From what we have gathered so far, the issue appears to be related to some of the recent versions of Android OS and Google Apps. This issue stems from these devices' "Cast" feature, which sends MDNS multicast discovery packets in order to discover and keep a live connection with Google products such as Google Home. These packets [are] normally sent in a 20-second interval. However, we have discovered that the devices will sometimes broadcast a large amount of these packets at a very high speed in a short amount of time. This occurs when the device is awakened from its "sleep" state, and could exceed more than 100,000 packets. The longer your device is in "sleep," the larger this packet burst will be. This issue may eventually cause some of router's primary features to shut down—including wireless connectivity.

For now, disconnecting your Google products from the network or disabling cast functionality seems to fix the issue. A Google spokesperson told Engadget, "We're aware that a small number of users are having issues, and our team is working quickly to share a solution."