What do these dates denote? Maybe whenever a birth/baptism certificate was issued?
Is there a column heading or is this in a page margin?
Typically printed baptismal records had extra columns for confirmations, and for comments. I've also seen vaccination records, emigration notes, parish transfers, death dates, etc. in the comments fields. (Marriage and burial records can also include a number of interesting details in the comments column).
It is probable from the format of the numbers, that some of the combinations are actually reference numbers to other records or correspondence to the parish.