I believe this is due to my regex logic not actually running on attempt. or the actual tests being run is taking variable $s1 for the failure test. rather than $s12

I am not sure to understand what you mean... Print the inputs to see which they are (and post them if you still have problems; it will be better than your code).
I am sure that there are no error in the fixed tests since they are the same in all languages.
You miss the fixed tests when you submit but you also miss the random ones.
Maybe take a new look at your code.
For now I consider the issue as resolved but you can post the inputs where you are failing and we will see which is the correct output needed in each case.
Cheers.