The problem is: your observation is incorrect. Probably, you just copied the text incorrectly, maybe even two times. In one place you have "(\\QCustomer ...)", in another place — "(\QCustomer ...)".
Both cases are incorrect.
First case: in C#, having
string value = "(\\QCustomer ...\\E)";
It compiles. It means that value is "(\QCustomer ...\E)". But these two escape sequences do not exist in .NET regular expressions.
The second case: C# tries to replace "\Q" with something, but this is a non-existing escape syntax. You could use '@' again. But again, the regular expression would make not much sense.
[EDIT]
So, this code would be incorrect:
using Regex = System.Text.RegularExpressions.Regex;
Regex regexTwo = new Regex("(\\QAmazon Verified Purchase\\E)");
[END EDIT]
Please fix it and try again. For further help, we would need to know the goal, formally and correctly described.
—SA