Please
compress and attach one of your hand history files to a
Support Ticket so that we can investigate the stat issue.
Stats should be combined across tables unless you have selected the session stats option by right clicking a player's HUD, or via the PT-icon. Note that your own stats are always shown as session-only to show your current table image.
If that isn't happening for you please restart PT4 and play 10 or 20 hands at a pair of tables which have the same player. Attach the PokerTracker4.log file from C:\Users\yourname\AppData\Local\PokerTracker 4\ (which you can access from the PT4 File menu) to a ticket along with a
screenshot showing both tables.