Launch: Regex is not working as expected in rule condition

I have a condition to execute in launch rule for "path without query string" condition type. The regex is simple to pass for all URLs except the url with specific path. Negative condition. Regex is (www)?silabs.com\/(?!developers\/usb-to-uart-bridge-vcp-drivers) and tested inside the launch itself using test button while adding the condition. After publishing , the condition is preventing the rule to execute for all the urls not just to mentioned path. 

Does the regex feature works in launch? i have tested my regex condition outside of launch also, works fine.