This is caused when AprilTags solution solving isn't able to work something out. It outputs directly to stderr: https://github.com/AprilRobotics/apriltag/blob/04c4ec3fbb9cbbec1344049323d24e752f01bf38/apriltag_pose.c#L441
I would suggest if the robot logging level is above logging.DEBUG then redirecting the stderr of apriltags to null.
Maybe something like this: https://stackoverflow.com/a/52442331/5006710
