TPMS question

Getting the “Tire Pressure Sensor Fault” message. Dash shows driver side front tire as no reading. All 4 sensors tested fine twice over 3 day span. Had tires rotated and all sensors re-learned and tested. All good. Like before, alert sounds after about 20-30 minutes of driving, but now it’s the driver side rear tire not showing a reading. Should I have sensor replaced even though supposedly fine? Is it a transponder or module issue??