Guided mode goes wrong after running for a while

Hi, I’m using guided mode to control a rover to go to waypoints I’m sending from a ground station. I’m using external positioning (indoor) that provides x, y, z and yaw info. I don’t use the mission mode because the sequence cannot be given at the start, so the only way I can think of is using guided mode.

Every time I run the rover, it can go to the expected waypoints correctly for the first 2 minutes (sometimes it can be slightly shorter or longer). Beyond this timeframe, the rover starts to circle around and has a hard time reaching the intended waypoint. Sometimes it can reach the waypoint by luck when circling around.

Below is the google drive link to the log file from one of my experiments. Sorry I cannot attach the log file here because the file is too big. On this log, it looks like the rover started to circle around starting from line 275000 and beyond.

What could be the cause of this erratic behavior? Do you have any suggestion on how to troubleshoot this problem? I was suspecting that the external positioning data (VISP’s Px, Py, Pz, Yaw) might have gone wrong, but they seem to be correct.

Really appreciate your suggestions. Many thanks.