At the polling stations in Virginia you were asked if you want to vote in the Republican or Democratic primary. You could choose which, regardless of your party affiliation.
This is anecdotal, but there was a lot of talk about Democrats and Independents, knowing that Biden was a shoo-in, choosing to vote for Haley as a way to repudiate Trump. Haley garnered 240,839 votes, 34.8% of GOP votes. I'm betting a good chunk of those were non-GPO voting anti-Trump.