Tested on https://zbw.folio.gbv.de (Poppy CSP#5), Bugfest Quesnelia, and Bugfest Ramsons.

Steps to recreate

1. Open the Agreements app and create a new agreement.

2. Add two agreement periods:

   • Period 1: Start = 01/01/2021, end = 12/31/2024

   • Period 2: Start = 01/01/2025, end = empty

3. Save the agreement.

4. Edit the agreement and remove period 2. Now try to save the agreement.

Expected behavior

• The agreement is being saved.

• The agreement only has one (current) period.

Actual behavior

• The agreement can't be saved and an error message is displayed: The following periods have overlapping dates: 1 & 2

Supplementary information

• Save without an end date in period 1 does not work as well.

• Change the start date of period 1 to 01/01/2026. This is after the end date of period 2 and should trick the validation, but it does not work as well.

• Set the end date of period 1 in the past (12/31/2023) is also not working.

• There seem to be no workaround that involves the UI.

• There doesn't seem to be a ticket yet.

Possible workaround:

Put a dummy period like 1/1/1000 and 2/2/1000 into the fields of the period to delete.