ShellyEM power factor flipping

About a month ago I got the basic ShellyEM to monitor my whole America power usage. I have standard single family center tapped 240V service (ie 2 120V hots sort of spinning around a neutral at 60Hz). I put a current clamp on each hot and connected the unit’s power for the neutral and all has been lovely as far as my primary goal of getting finer resolution on my energy usage. What’s confusing me is the power factor readings I’m getting. 1) I’m getting negative readings and 2) they’ll flip from positive to negative and back again. When I say negative, I don’t mean like -0.1, I mean like -0.88 or -0.95. Like it’s an entirely rational PF number, just negative for some reason. It’s reading negative in the Shelly WedUI, so it’s not a problem with HA, just wondering if anyone else is seeing things like this and if there’s an easy fix?