JabRef version

Latest development branch build (please note build date below)

Operating system

Windows

Details on version and operating system

Windows 10

Checked with the latest development build

• I made a backup of my libraries before testing the latest development version.
• I have tested the latest development version and the problem persists

Steps to reproduce the behaviour

Steps to reproduce:
Part 1:

1. Create a new library.
2. Click on Add group button.
3. Input name test1 for the group and create the group.
4. Create 2 articles in All entries.
5. Input author field with steven and mike for each article respectively.

Part 2:

1. Right click on test1 group -> Edit group
2. Select Searching for a keyword under Collect by.
3. Input author as field and steven as keyword, then click on ok button and ok button for warning dialog.
   (test1 group has a steven article entry)

Part 3:

1. Right click on test1 group -> Edit group
2. Select Searching for a keyword under Collect by.
3. Input author as field and mike as keyword, then click on ok button and ok button for warning dialog.
   (test1 group now has 2 articles which are steven,mike and mike articles)

ACTUAL:
However, 1 of the articles' author field has been merged to steven,mike. Is this an expected behaviour?
From my understanding, Collect by should only return filtered entries without any entries modification.

Appendix

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Paste an excerpt of your log file here