Pin 37 on the CYRF IC must be connected to ground. It has been left to float. This is a serious design oversight, causing intermittent operation under certain dynamic conditions. Not an opinion that warrants debate but a fact contained in the design documentation ignored by the Spektrum designer and confirmed by the chip designer, Cypress Semiconductor Technical Support. Unfortunately this is one of many poor design features. This is only a problem on the RX side. The TX module is a commercial off the shelf unit and was designed correctly by that vendor. It is not safe to fly. It is too be expected Spektrum will deny this.