Frederic Dubut from Microsoft said Bing "may still crawl parameterized URLs occasionally." He said that the "most common parameters are taken into account in indexing" but it still may crawl the other parameterized URLs here and there.
Frederic said this Twitter where he was asked why is Bing indexing URL tracking parameters for some sites.
Here is the conversation on Twitter:
Are you asking why we are indexing duplicate URLs in spite of normalizing UTM (and other tracking) parameters, or are you asking if we are normalizing UTM parameters in the first place? Do you have a specific example you'd like us to look at?
— Frédéric Dubut (@CoperniX) April 8, 2021
cc @facan since it's about indexing
The most common parameters are taken into account in indexing but we may still crawl parameterized URLs occasionally.
— Frédéric Dubut (@CoperniX) April 9, 2021
I don't think this is particularly new.
Forum discussion at Twitter.