Guys
As suggested @matthijs here increasing clock error for receive windows solved all my OTAA join with LMIC (on Arduino Zero) but may apply on RPI, worth trying this fix (here 1% error more) you can con even on 2% or 3%
LMIC_setClockError(MAX_CLOCK_ERROR * 1 / 100);
Works perfectly with Loraspi board with RFM95