The Los Angeles Times reports Iranian-American U.S. citizens were detained at the Canadian border and questioned for several hours before being readmitted. As you might imagine, they were incensed and the CBP claims they were not profiled.
OTOH, apparently Suleimani alleged the existence of Iranian sleeper cells of covert agents in the U.S. Such cells are made up of naturalized U.S. citizens of Lebanese Shia or Iranian birth. See an article in The Federalist about Iran’s sleepers in the U.S. and Latin America.
Caution by CBP seems entirely warranted. Don’t you suppose the FBI is taking a closer look at clusters of U.S. residents of Lebanese or Iranian birth? I certainly hope they are, failure to do so would constitute dereliction of duty.