I do believe I fixed this along with another issue I was having by installing RealVNC as the listener on the Mac as opposed to enabling Screen Sharing in the Sharing prefs.
For reference, this also helped because I wanted a way to view the user's screen without consent or password. Screen Sharing from Apple dumps 3rd party VNC clients to a login screen, at which point if I want to view the user's screen I'd have to type in their password, which is not good. If using Apple's VNC viewer you have the option to connect to the console window but the user must give consent. RealVNC addresses both of those concerns.