Canonical question for cross-listed product listings

[LivDetrick]

We have products that are listed across multiple categories. This results in muliple urls for the PDP, for example:

mystore.com/shirts/shirt-101.html

mystore.com/shirts/pink-shirts/shirt-101.html

They make use of the canonical tag and point back to only one product listing url, however Google has indexed both urls in some cases.

Has anyone else run up against this and does anyone have advice on how this should be handled?

[LivDetrick]

Thanks for the info. My concern is that there are some instances where Google is splitting the traffic between two PDP urls. I guess it's good to know it is a problem others have. From what I've read and what you've said, I don't see a solution without eliminating cross-listing of PDP's between relevant categories, and doing that (I think) would make for a poor user shopping experience.

[GastonRiera]

Hi Liv,

There aren't quick solutions for these cases. 
My usual approach is to rely on Google, its algorithm will eventually get the canonical tag.

Its pertinent to understand that a canonical tag DOES NOT prevent a page to be indexed. The idea behind this signal is that Google would show the canonical version of the URL when it could have been the actual page.
I need to clarify this case, because when performing a site: search we will often find that canonicalised page there, but it usually does not get any traffic from Google.

Another thing to consider IS UP TO GOOGLE to decide whether to honour and consider your canonical suggestion. I'd try that page in the URL inspection tool to see what Google is considering to be the canonical version. 
And, last but not least, canonical works when two pages are (almost) identical, this is not a simple way to clean pages from google's index or to softly redirect traffic from one page to another without server redirects, I've seen this and many clients were really furious because it didn't work.

Hope it helps.
Best luck.

PS, just in case other users need it, some resources about canonicalization:

• Canonicalization - Moz Learning Center
• Consolidate Duplicate URL, canonicals - Google Search Help