Google Confirms Indexing Problems with Mobile, and Canonicalization

[engine]

Google's Search Liason account has confirmed two indexing problems it's investigating. Mobile-indexing and canonicalization issues mean that pagrs are not getting indexed.

[mobile.twitter.com...]

[Robert Charlton]

engine, thanks. We've been actively discussing the canonicalization issues as they've seemed to be applying to a site in this thread....

Google selects unrelated URLs as canonical
https://www.webmasterworld.com/google/5011109.htm [webmasterworld.com]

I suggest reading the thread as we progress, for what I'm thinking describes the problem historically and how it's been progressing. I don't know whether Google has stated it specifically, but my guess is that it's related to the error message...

Error is "Duplicate, submitted URL not selected as canonical"..

It's an issue that's surfaced in Google from time to time... well known by John Mueller... and the current gibberish in canonicals that users are reporting in Google probably stems from a failed attempt to fix this. That's a guess, piecing together material discussed in the thread I mention. We'll continue discussion in that thread, which shouldn't preclude any more general discussion here. I'm very curious, eg, whether the users who have been having the problem are using CMSs like WordPress, which result in a lot of dupe content on various pages.

Haven't heard any specifics about what the mobile problems might be. Thanks.