Sorry for the issue. That is annoying. That said, if it is the culprit - I would avoid it for now while you troubleshoot. I'll note this as an issue and will try and get into on that for you, as well. I've heard of others using sidecar (and it sounds cool), so it's possible that it might be something that we could fix. I'll have to ask for your patience, though, as I personally don't have an iPad Pro to troubleshoot with.
Still don't have any new info after searching around. Are you using the iPad as a Program Monitor or as more of a Project panel location? I would recommend the latter. Please also be sure that the device is sufficiently powered up. Definitely report the issue here: Premiere Pro User Voice