I just completed a website crawl on my site to vet SEO, which should return 119 pages. The results are around 490, with errors being returned showing hundreds of 404 pages with strange URLs. These follow a roughly similar pattern, like so:
Where the actual live page looks like this (please note that this is a dummy URL):
However, there are many 404 errors being returned when crawling the site that look similar or identical to these:
Currently, I cannot find any specific literature on what may be causing this - at first I thought it may be sitemap related, but attempting to re-run a sitemap generator also indicates over 490 pages which is very odd. I cannot see any of these additional pages on the IIS server system where the site is hosted, only the 119 that should be there.
I am totally stumped at this point! What could be causing this?