UPDATE: Microsoft says that they have now removed the detection from the latest malware definitions.
It seems like Windows Defender just got an update that mistakes Looking Glass host (reported version: B2-rc4-0-g969effedde) for a “Wacatac” trojan or something. I’ve had the current version of LG installed for some time so this is quite clearly a Windows Defender false positive.
So beware when installing Windows updates! You might want to allowlist LG before this happens to you too.