It sounds like typical example of asynchronous development.

He seems to spell phonetically which is a good start and upper case/lower case and punctuation comes in 1st and 2nd grades. I think our kids learn quicker using phonics and sounding out.

I remember my DD spelled "tisshoe" instead of "tissue" when she was little. They will make mistakes but 8 out of 10 times, they will get it right.