Duplicate pages appearing in IDC Class Verify

Came across a weird issue in our customer’s newly-provisioned SaaS IDC. When importing a batch of single-page documents, often a duplicate page will appear as page 2. The page is an exact copy of the first one, and it definitely isn’t in the source PDF.

I have a support request open but they’re being quite slow, so I was wondering if anyone else had come across this issue and if so, how was it fixed?

I’ve attached a screenshot to illustrate (censored some private info)

All PDFs were single-page documents. As you can see, Document 1 is unaffected, but documents 2 and 3 have a page 2, which is an exact copy of page 1