Site runs with a handful of template routes that uses the {page:pagination} construct to allow routing of paginated output.

Worked fine up to 3.5.6.

Updated EE to 3.5.9, and while it generally has worked fine, I found all the routes that include {page:pagination} simply stopped working - generating 404 errors.

What seems to be happening is that the {page:pagination} term is working OK when there is a pagination term present in URL, but throwing a 404 otherwise. But if you eliminate the pagination element from the route, anything with a pagination term triggers a 404 (regardless of setting of ‘segments required’).

So I’ve created a simple test case and that fails too.

I have two identical templates. Both generate a simple text output.

I have created two routes in Template Routing to handle. “Segments Required?” is set to no for both.

A simple test setup follows:

You can try out these tests on the live site by using the links in table above.

I am perplexed as to what to try / do to fix this - nothing changed in the routing rules before / after the upgrade.

I am able to work around the bug on live site thanks to static caching - I manually created the right rules to get the ‘no pagination’ pages and put them in the static cache, and put the pagination term into the routes to generate the paginated cases - but this is not a viable solution even for short term.