JIRA Issue Macro doesn't differentiate custom fields with different casing

JIRA Issue Macro doesn't differentiate custom fields with different casing e.g., "Start Date" and "Start date".

Steps to reproduce:

• Create 2 custom fields "Start Date" and "Start date" in JIRA and show them in issues
• Create a page in Confluence and add the JIRA Issue Macro to that page
• Edit that macro to display some issues from JIRA

Expected result:
Both "Start Date" and "Start date" are shown in the macro's "Display Options"

Actual result:
Only "Start date" is available in the macro's "Display Options"
If we add a Filter Result Macro to the same page, both "Start Date" and "Start date" show in "Select a field..."

Workaround:
Rename one of those fields as cf[customfieldid] cannot be used in the macro's columns.