Excess return of GCS FailSafe, even if my antenna is 2m from the GCS!

Hello friends, I have a situation that I didn’t have before, I am receiving eventual failsafe due to loss of GCS Beatheart and followed by “GCS cleared” in less than 2 seconds, I can only fly with FS_OPTION = 2 to avoid premature return.

I remember that the rule for Copter is 5 seconds time out, right? why does my drone activate GCS FAIL SAFE?

Thank you who can enlighten me, I will publish a log to demonstrate the problem.

I am using HOLYBRO 500MW TELEMETRY 915MHZ RADIO, Mission Planner 1.3.70.

Messenger Tab:
GCS Failsafe Cleared
GCS Failsafe

Tlog:
https://drive.google.com/open?id=1gox6xMSxL7u600F98I-KgCv6Svl5BYki