Conditional Formatting working in Desktop, not in Service

I see several posts from way back which paints this as an intermittent problem but what really is the cause here? The screenshot below shows the Service (left) and Desktop (right) versions of the same report and only the Desktop version is showing the conditional formatting properly.

(left) Service, (right) Desktop

This is how I set up the rule. I assume that since it is working as intended in the Desktop version, it means the way I set up the rule is correct - meaning the problem is with the service.