My baby is getting scared for no reason and suddenly start crying like he seeing a ghost or something?

One time going into the garage (which he has been there before and it was okay) but since he got scared twice in row i stop taking him there thinking it’s hot are in there or something is scaring him.

and second time when seeing his brother on FaceTime. Which he has done it too many time and it was okay but today two time he sees his brother on FaceTime and he start crying his loung out. Like he is scared or seeing a ghost

Is that normal ? This happened 2 times since he turned 4 months. He is 5 months old now.

Please help

Thank you