One domain has 136,000 indexed pages, while the other has only 20,000 pages indexed. The website itself doesn't have more than 50,000 pages indexed anyhow. Both domains are the same age, and in the past, both had the same number of pages indexed - about 40,000. How do you explain that phenomenon ?
One probably has more or better links pointing to it and Google feels it is more important, therefore it does a deeper crawl and index I *think* I am understanding the question after reading it a few times
I would guess they are a copy of themselves and the duplicate content filters are blocking out the second.
About five files create more than 50,000 dynamic pages. The pages are not duplicated. The content is different from page to page. The structure is the same for almost all pages - does it mean they're dup? I guess/hope not. What I assume is that google yet hasn't erased "dead" pages from one domain, while on the other one, it has erased all dead pages, but not yet indexed the new ones. Dead page is a page which does not longer exist, since the activity had been cancelled. What do you think?