When data is pointing opposite directions, it is said to be diametrically bimodal. The average angle of this data would be at a right angle of the true mean angle and a poor representation of the data. An angle doubling procedure is applied to the cases that were found to be diametrically bimodal to result in a more representative output of the mean orientation.
This is an informational message; no further action is necessary. As stated in the message, for the affected cases, the output was corrected for better representation of the mean direction.