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I believe that the dynamically appended urls are necessary for navigation
I am seeing massive rewriting of all my page titles now.I'm getting that too but in the opposite way. I have pages that include the site title after a hyphen "Green Item Page - Widget Website" and some of the pages that don't use the site title are having it added in the SERPs like internal site search results pages "Results for Green Widgets" becomes "Results for Green Widgets - Widget Website".
I've seen something similar in the past and wonder it's not a subtle hint to start adding the site title to the pages without it.
Google tailors the click-able title to specific search terms