Door frame size
Speculation without a pic, but it sounds like some clueless person tried to install a modern width door jamb unit in a wall that is thicker than found in modern construction. It is not uncommon for older houses to have thicker walls than newer construction due to the dimensions of old, rough cut lumber vs modern dressed framing lumber, and the varying thickness of plaster jobs. If you want to save the units, thay will have to be removed and installed so that the hinge side of the jamb is flush with the wall surface, than you can add extensions to the other side to flush it out; then door casing as usual. If you want to replace the unit, use a lumber yard or mill supplier that will order custom width jambs on the unit. It will cost more, but is worth it IMO. Be sure to measure the wall thickness in at least 3 or 4 places and use the thickest dimension.