Could be either a button buck or a short spike, most likely the latter. 1 1/2 year-old bucks generally "cruise", or migrate, from their home turf where they were raised to a new territory where they will establish a home range. Sometimes these migrations can cover less than a mile, or sometimes they may cover many miles. This is the chief mechanism by which whitetail deer avoid inbreeding. These migrations usually occur anywhere from late summer to late winter in the buck's first full year (with hard antlers).
Button bucks (1/2 year old) are seldom hormonally ready for this transition, but it is possible a rare deer might do it, especially if its mother has been lost.
Either way, it sounds like your deer may either be "feeling out" a new home range, or may have already established it.