Issue Summary

You cannot use a single custom field with different names in different projects in Jira Cloud. The field name is global, and JQL/search will only recognize that global name or the field ID. The only per-project customization available is the field description, not the field name.

Example:
Use 1 custom field, allow this field to be used with different names in different projects. For example:

• Project A uses custom field called “Category”
• Project B uses custom field called “Type”
• Both fields have a custom field ID of 12345.

The field should be identified appropriately in each project’s screen and the field should be usable in JQL/Basic Search with either field name and/or project-specific context.

We've this feature request opened for JRASERVER as well.
https://jira.atlassian.com/browse/JRASERVER-66199 

Workaround

Currently there is no known workaround for this behavior. A workaround will be added here when available