LO started hand flapping (opening and closing hands)

My LO is almost 14 months and he just started hand flapping. I’m not sure if this is something that I should be concerned about as I know it can be an indicator of autism. He has no other signs besides the hand flapping. Anyone else’s LO do this? I plan to mention it to my doctor at his 15 moth appointment but in the mean time I’m just wondering if anyone has any insight about this?