I haven't come across one in my social life or while canvassing for a number of years, but there were definitely instances where, after various conversations, it became pretty clear that a "staunch" Republican acquaintance was actually totally onboard with key Democratic aspirations and opposed to Republican cuts in benefits, and whatnot -- like they voted and didn't notice what the Republicans they voted for actually did.
Seemed to me it was usually some mix of (1) I'm from a family of life-long Republicans, (2) a fantasy view of what "Republican values" are, (3) a warped view of what "Democratic values" are.
Then, there are the "abortion is murder and must be banned" people. When I've managed to engage such folk on other things, a few were pretty solidly in the Democratic camp on those other things. Some were even pretty mixed up on their position on abortion when asked questions like, "So, women who have abortions should be thrown in jail?" or "A doctor who gives a woman a safe abortion to save her from harming herself should be put in jail?" When the answer to things like that was something like "No, nobody should be sent to jail, but it should be illegal. It must stop. It's murder." To which the follow ups are things like: "So, you want to make it a crime, but not put anyone in jail?" "So, you think making it a crime will stop women who don't share your religious belief about abortion from finding a way to end a pregnancy they are determined to end?"
Don't know if I actually converted anyone, but was often shocked to find anti-abortion people -- people so staunch in their belief that they would ignore everything else they opposed about a candidate -- who had never given any consideration to such questions. (At least it sure looked that way given the knitted brows and stammering.) I think a lot of those folks just blithely believed that making a "bad thing" illegal makes it magically stop.