HTML / XML / JS, low-level validity (cross-cutting)MediumInferred
Faulty pagination markup
What it is
Misused rel=next/prev or broken pagination.
Why it matters
Confuses sequence understanding/crawl.
How to fix it
Implement clean paginated URLs.
Impact
Low-medium. Inferred.
Evidence
Clean pagination aids crawl of sequences. Google Search Central, Large site owner’s guide to managing crawl budget