Have encounter the same issue as you with the latest FW -release (07.13.1).
Teltonika have made a major change blocking “ubus call” and suggest to use the API-requests instead.
After Teltonika confirmed the forwarding moving strategy blocking “ubus call” i tried the suggested API approach, documented in this case:
CLI Modbus scripts debricated in 07.13.1?
The API-solution is for me really slow and inconsistent (4-12 sec. between requests) compared to ubus call and the workflow troublesome compared to direct scripting. With this performance it is not usable for my current applications.
I hope Teltonika will make a opening for us favoring scripting and response requirements…