Why does the monthly deleted spike not result in a decrease in active listings?

When aggregating and charting LinkUp monthly (or weekly) data points, we often can observe a spike in deleted listings, which does not affect the active listings in the most recent month(or week). (see below for example)

We can see in this chart, that there is a large spike in deleted listings, and also an increase in active listings in the most recent month. This may seem counterintuitive at first.

Why is active not decreasing?

Active listings are defined as any job listings posted on an employer's (or group of employers, in this case, the US) career page for any duration within a given period. Whether a listing is posted for 1 day or 30 days during a month, it is counted as 1 active listing for that month. If a job is removed after a day, it is still considered active for that month but will be excluded from the following month's active count. This means that almost all deleted listings within a month will still be included in the active count for that month and won't be removed until the following month's count.  
Note jobs deleted on the first day of the month would not be counted active for that month, since it was not active at any point that month.

Example

This hash was created on 2024-07-05, Below is how it would be counted on a monthly aggregation.
 

2024-07 +1 Created, +1 Active
2024-08 +1 Active, + 1 Deleted
2024-09 -1 Active