Google Assistant is one of the more powerful AI platforms out there right now, but it isn't without its flaws. It's still in its early stages, and is still learning from users to process language more naturally and expand its command capabilities, with IFTTT integration being one of its most recent improvements. On a more basic level, of course, Google Assistant still has its odd bugs here and there. One, found recently and brought to light on XDA Developers, is a bug with any and all forms of VPNs, or virtual private networks. Commonly used for security, VPNs can be instituted at the level of the device or the connection, and it seems that Google Assistant is not very fond of them.
While various reports are coming in from various sources, the consensus seems to be that any sort of VPN activity at all will cause Google Assistant to show its offline warning, telling the user that their device is not currently connected to the internet, which means that Google Assistant won't be able to do much. In some cases, the app still works wonderfully, while other users are finding that the bug either renders the Google Assistant entirely inoperable or disabling the Screen Search functionality that replaced Google Now on Tap on devices with Google Assistant enabled.
Reports are scattered between those who enabled Google Assistant on their devices via build.prop tweaks, those who used an Xposed module, and Pixel owners who are using Google Assistant with Google's blessing. Likewise, those reports are scattered across compatible Android versions, and across different VPN-based apps and types of VPNs, with some reporting that things as innocuous as Google's Wi-Fi Assistant have managed to trigger the bug. The level of functionality lost and what may trigger the bug seem almost random, but most who use a VPN on their home network seem to be reporting that they're simply seeing the warning, with full function still intact. The latest beta version of the Google App reportedly has a fix for those who have full functionality outside of Screen Search, but this has yet to be verified. As with any other issue, the community is investigating it, and Google likely is too, but for now, the best bet is to keep any Google Assistant-compatible devices off of VPNs, if at all possible.