Do you use an eVar as "internal search term"? if yes, what is expiry?
If you track the "internal search term" in an eVar with eg. visit exporation, you would see all orders where the user search for the desired string before the order. the reason is that the eVar is valid until expiry, therefore the segment includes more than just a single hit/image request.
you can see the difference if you add the corresponding instance metric to the segment ("internal search term instances). this way you would only receive hits where the search term is sent to adobe (in image request).
thats really a great visualization! I would add another hit before the internal search term to see the different result using a hit vs visit container on the evar (the hit container would start at the second hit, not including the first page - since the search is on the second hit...)