Unable to remove buff

[Zelren]

Describe the bug
One of my players added a buff via his charactersheet with a duration of 1 minute. We are now unable to remove the buff and receive the following error message: "Argument number 2 "duration" to function "json.get" must be an integer. Error trace : Buffs@Lib:Character <<< macroLink".

To Reproduce
Steps to reproduce the behavior:

1. Go to the character sheet
2. Click on Buffs
3. Add new Buff [name:" +2 AC, +1 Aktion" duration: 1 minute]. Confirm.
4. click on buffs, no prompt/dialog opens up
5. See error

Expected behavior
Expected the buff dialog menu to open and be able to remove the buff via the remove tab.

Screenshots
If applicable, add screenshots to help explain your problem.

Desktop (please complete the following information):

• OS: Windows 10
• Maptool Version 1.8.5
• Framework Version 2.5.6