Summary

Appending value by using Update Issue Custom Field post-function will replace the current value instead.

Steps to Reproduce

1. Create a new Text Field (single line) custom field
2. Go to workflow and edit any transition (e.g In Progress -> In Review)
3. Add Update Issue Custom Field post-functions to the transition:
   • The Number of the issue will be set to 123.
   • The value 1 will be appended to field Number, or set if it is a multi field. (tick append)
   • 
4. Publish workflow
5. Create a new issue
6. Transition the issue from In Progress to In Review

Actual Result

The current value will be replaced instead of appended (updated value: 1):

Expected Result

The current value is appended with the value set in the second post-function (appended value: 1231)