Nearly all compasses have built in compensation magnets. It is possible that yours have been tweaked incorrectly, or that they simply have not been adjusted to minimize deviation. You will most likely be able to remove much or even all of your current
deviation by going through the ritual of adjustment. Your compass owner's manual (if available) should outline the process, or one can find non-proprietary instructions on line.
Let us know how it turns out, and good luck, too!
Jim and Ann s/v Insatiable II lying Morning Cove, NSW, Oz