Two Noble Kinsmen (or, the problem of expectations when starting a book/play)

I am currently reading through Shakespeare's Two Noble Kinsmen because it is one of the last of his works that I have not read yet. I thought I would pause to reflect here and ask anyone who has read this play (or anyone in general) if the following has happened to them:

The popular story behind this play is that it is a collaborative work between Shakespeare and Fletcher. Thus, it is not "pure Shakespeare." I tried to get into the play without considering this fact but unfortunately my mind keeps jumping to "oh, that passage in the High Medieval rhetoric is not Shakespeare," or "these flat nameless characters are not indicative of Shakespeare."

There are parts of this play I am really enjoying (mainly the two eponymous characters) but I am unable to judge it without interference from the fact that this is a "lesser Shakespeare" compared to his others.

Has anyone who read Two Noble Kinsmen experienced this? Or, if you have not, can you read a work by what you consider a "bad author" without that stipulation? If the author of, let's say, Twilight published another book that had nothing to do with this series, could you read it without the expectation that it will be terrible?

I've not read Two Noble Kinsmen, but I felt the same way when I had to read Pericles, Prince of Tyre at university. I remember thinking that it was poorly structured - it just didn't feel like a Shakespeare play. Looking back, I can't help but feel that the doubts about its authorship influenced my judgment.