If I have understood correctly you are referring to the "visit_page_num" column. As per the current design of Analytics, if the timestamp is the same for two hits then we use the combination of columns "hitid_high" & "hitid_low". Any hit whose hitid value is less will appear first followed by the one whose hitid value is higher.
So, I will suggest you to get in touch with your implementation team to identify why some of the hits have the same timestamp value. Also, one thing to note here, in case of data feeds we only look at the timestamp till seconds. If there are two hits that were received with the difference of few milliseconds then again the above-mentioned method will be followed to identify the order of the hits.
Hope this helps. Please let me know in case of any further questions.