Regression on matchHeader with commas ?

[AlexTess]

Hello,

I'm in the process of upgrading from 3.5.24 to latest version ( 4.1.6) and I've come accross what seems to be a regression in the Pact Verification phase on match header.

My consumer contract contains the following in the dsl :

.matchHeader("Last-Modified", "[a-zA-Z]{3}, [0-9]{1,2} [a-zA-Z]{3} [0-9]{4} [0-9]{2}:[0-9]{2}:[0-9]{2} [A-Z]{3}",
                        "Fri, 7 Jun 2019 16:47:07 GMT")

When running the pact verification, I'm getting the following errors:

1) Verifying a pact between xxx and yyy - Scenario: refresh 

    1.1) HeaderMismatch: Expected 'Fri' to match '[a-zA-Z]{3}, [0-9]{1,2} [a-zA-Z]{3} [0-9]{4} [0-9]{2}:[0-9]{2}:[0-9]{2} [A-Z]{3}'

    1.2) HeaderMismatch: Expected '3 Jul 2020 14:39:44 GMT' to match '[a-zA-Z]{3}, [0-9]{1,2} [a-zA-Z]{3} [0-9]{4} [0-9]{2}:[0-9]{2}:[0-9]{2} [A-Z]{3}'

I should point out this works fine with previous 3.5.24 version, so there is no issue with the data generated itself.
the header itself matches the regex
Fri, 03 Jul 2020 14:49:46 GMT

is there something I'm missing? it seems the comma is somehow an issue in the verify ?
Im using pact provider verify through this classical code:

    void testTemplate(Pact pact, Interaction interaction, HttpRequest request, PactVerificationContext context) {
        try{
                context.verifyInteraction();

   }

Thanks in advance for any tips.

[uglyog]

Result of #997

[uglyog]

4.1.7 has been released with this fix