There is a known issue (GOV-453 and PRO-2969) with the Size for apps larger than approximately 2GB. For more help on this, you should file something with Qlik Support about "Negative File Sizes".
Concerning the #rows, there is also a known issue for multi-cluster scans in which it is double counting the #rows. You might try selecting a specific qvw and looking at the "Singe QVW detail" for the Total Number of Rows.