removing subclaims

ok so i have a large area that i was original going to divide into subclaims into 4 smaller areas to rent out.
but recently i have changed my ideas about this, i changed my shovel into subclaim mode, stood in the sub claim, did the /removeclaim command, this removed my subclaims and kept my basic claim as would be expected.

then i noticed that every time i removed my subclaims it was reducing the size of the subclaim from my claim blocks…….

so i thought id let you all know cause this is clearly an unintended bug.