f you're sure the devices are up to date and are syncing correctly, then its probably down to sync timing mismatches. It can get very involved across devices and the web, but basically there are 3 things to keep in mind that might help avoid data clashes:
The account on the web is the master account, all devices sync to it and reflect the data stored there, devices do not sync to each other.
The last save wins. Every action you take on mobile or web has a time stamp on it and the last time stamped save will end up being the final data set, no matter what order data syncs to the cloud in. This can result in data loss if, for example, a session is started on a laptop before the client visit then saved and sync'd, then completed on a mobile device during the visit and saved again, then the save button is hit on the partially completed session on the laptop before the mobile has a chance to sync. In this example all the work done on the mobile could be lost, as the last save on the laptop has the most recent time stamp.
The mobile app only syncs while the Cavanti app is open and active. If the app or device goes to sleep, the sync will stop which can result in data from that device being missing on the web and thus all other devices.