Since Canion seems to be the app most affected by this issue I thought I would share the details in this thread.
As we've suspected for a while, early OBDLink LX adaptors have a Bluetooth firmware bug that caused loss of pairing. This has now at last been officially acknowledged by Scantool and an RMA program is available to send the device back to have the Bluetooth firmware reprogrammed at the factory, then sent back to you. Unfortunately the Bluetooth firmware cannot be updated in the field - updating using the OBDLink Android app does NOT update the Bluetooth firmware, only the firmware for the main STN11xx chip.
See the following threads:https://www.scantool.net/forum/index.php?topic=15265.0https://www.scantool.net/forum/index.php?topic=15478.0https://www.scantool.net/forum/index.php?topic=15460.0
This is a thread from last year where I helped diagnose the issue:https://www.scantool.net/forum/index.php?topic=14605.0
In short if your adaptor is R4 or earlier it needs the Bluetooth firmware update to solve the issue with pairing constantly being lost with Canion. (Other apps are affected too, but not as much)
I was lucky enough to be sent an R9 adaptor last year as part of the troubleshooting process and can confirm that I don't have any Bluetooth pairing issues with the R9 revision. Although I was sent a new one without needing to send the old one back it looks like now they have openly acknowledged the problem and have a fix they asking for the devices to be RMA'ed in for a firmware update rather than sending out new adaptors, which is probably fair enough as it would probably be cripplingly expensive to just send out replacements to anyone affected!