Split operation fails for large PDF

I'm using the .NET SDK to parse some PDFs of varying sizes, one is 2000 pages and 2MB, other is 6000 pages and around 15MB. I only need the first page of both these PDFs to extract information from, and so the workflow has been to Split the PDF into that first page and then feed that into Extract to get the table information. This works flawlessly for the smaller file but fails at the Split operation consistently for the larger file. I've tried a similar workflow with the Delete operation and that does not work as well. Please advise.