This same test code(Adafruit examples and Arduino Nanos) work perfect with SIM800L, SimCom A7670G module, but not with a SimCom SIM7670G module.
When receiving any length test SMS message, the last character disappears, regardless of message length, Like send: "Test edaboard" received: "Test edaboar".
The SIM7670Gs tested receive the full SMS message when tested with direct USB connection (Putty) and AT Command Tester.