116v

[-JKP-]

The first half of the 15th century was a transitional period for quite a few things.

This may not explain the "a", but it's something to consider...

• In the very late 14th century and early 15th century, they were switching from double-story to single-story "a" and many scribes wrote it both ways in the same line.
  
• By the late 15th century, the double-story a was mostly obsolete for handwritten texts (although the printing companies designed typestyles that included double-story a, so it never disappeared entirely).
  
• The same with numbers, they were switching from the old style of Indic-Arabic numbers to the modern style and some scribes mixed up the two styles. The old style was almost gone by the end of the 15th century.
  

So... maybe (just maybe, I'm not sure), the scribe wrote one and changed it to the other.