Thank for your Query
Bluetooth connection works the same as USB wire connection, so, every time you save changes you should receive a confirmation message indicating the changes have been saved, please make sure this confirmation message is shown.
Also, make sure you have the latest Firmwae available for your device. Firmware updates usually bring bug fixes and overall performance improvements.
In order to analyse your issue deeply, and/or get the latest firmware I would suggest reaching out to us via VIP Helpdesk or contacting your Sales Manager/Distributor. If you don't have any contacts with our Sales managers, please contact them on our official website https://teltonika-gps.com/ and click on the "Contact Us" button. When you will click, please fill out the form and submit it.
Note: as a topic, please choose "Vehicle Telematics" or you can send an e-mail with the description of your situation to firstname.lastname@example.org
Thank you in advance.