The Rocks have had a point taken off their 2018-19 because of an administrative error.
It does not affect their final league placing - they finished 14th with 57 points, seven clear of 15th-placed AFC Hornchurch.
A club statement released on Tuesday morning said: "We have been deducted one point by the Bostik League for the season that has just been completed.
"This was as a result of an administrative error in connection with a player’s registration which affected one match which was drawn, hence the deduction of one point."
No details of the game or player in question have been revealed.