
Looking closer,there is a dent in the lower part of the cancel.So it looks like the
cancel is genuine.That leaves 2 or 3 possible things.
1)Unofficial use and cancel of the bisect by a postal clerk(Mixed up date slugs),cover really sent.
2)Manipulated cover front by removal of prior stamp(s) and a genuine favor cancel on the bisect.This may be far fetched given the early date of the cover,but possible.
3) ???