I remember this happening to my car when it was near new. ~1500km. I turned it on in the morning (cold start). Then after driving off for a few seconds...the "AT" light came on. Checked the warning guidance in the infotainment and it said somtehing was very wrong with the AT and i should get it checked by Mazda.
However driving for a few more minutes....the warning disappeared including the light. Must be like a bug/glitch...
However driving for a few more minutes....the warning disappeared including the light. Must be like a bug/glitch...