Type of perforator unknown, treadle type perforators are known in some countries.
The operator (however way) punches the first line across the sheet,
sees it has cut off some of the design, and re perforates in the correct position.
Sadly the stamp has ripped off at the wrong line of perforations.
This set exists in all sorts of weird and wonderful varieties, human nature being what it is, do not dismiss this was done purposefully.