it’s the first I’ve heard of maybe a US citizen being deported.

It’s been happening for years. From the Washington Post:

The U.S. government does not release data on how often ICE wrongfully detains or deports U.S. citizens. But investigations by media outlets, research institutes and oversight agencies have revealed that ICE has arrested, detained, deported and issued detainers — requests to local jails to hold a person in custody — for thousands of citizens since the agency was created in 2003. One 2011 study estimated that roughly 1 to 1.5 percent of deportees are U.S. citizens.

https://archive.is/20250411190043/https://www.washingtonpost.com/immigration/2025/04/05/us-citizens-deported-immigration/