Issue Summary

Adding a custom field with certain characters in the field name like "[sub]-1" in the "Edit work item fields" action in the automation rule leads to error:

"Error loading component
An unknown error occurred. Please reload and try again."

Known bad character sequences

These will reproduce the bug. Note that it only causes the bug if these are at the end __ of the Custom Field name. If you add any general text after these characters, the bug won't happen.

[anytext]-1
[]-1 

Known acceptable characters

If these are at the end of the custom field name, it's fine. The bug won't happen.

[anytext]-
[anytext]-a
]-1
[]1
1

Steps to Reproduce

1. Create a custom field named "Test [anytext]-1". It can be any type of field (e.g. short text).
2. Create an automation rule
   1. Add any trigger
   2. Add Action: "Edit work item fields"
   3. Select field "Test [anytext]-1" (no need to add any text into it)
   4. Click Next

Expected Results

Rule tree is shown and you can add more actions.

Actual Results

The below error is thrown:

Error loading componentAn unknown error occurred. Please reload and try again. 

Refreshing the page allows you to edit the "Edit work item fields" action but switching to any other component in the rule leads to the same error.

Workaround

Rename the custom field name to remove special characters part.