Q.Japanese maple with uneven leaf sizes and sparse leafing
I have a green and purple Japanese maple that was planted in my yard two years ago. It is about 7 feet tall and produced a beautiful crop of leaves last year that went from bright red to green and purple, and was very healthy looking.
This year something odd has happened. The leaves are radically uneven in size. Last year all the leaves were more or less the same size. This year there are small leaves, the more normal sized leaves, and truly large leave looking almost like a full sized maple. The branches are rather sparse on the lower limbs as well, and there are many, many buds on all branches that look as if they tried to come forth and could not for some reason.
I am quite concerned and at a loss. The other Japanese maples in the same space all look fantastic. I live a few blocks from the Monterey Bay, and the weather has been rather mild for the past two months. Thank you for any ideas and suggestions.

This sounds like an unusual problem. The best advice I can give is to take a sample of branches, and maybe some soil around the plant, to your local extension service, and see if they can analyze the problem. This site will help you locate an extension office: https://www.gardeningknowhow.com/extension-search/