[Dan Walker]

I have used Timber Mate

https://ca.search.yahoo.com/yhs/search?p...87ec434f84

Timber mate is a grain filler  [not a wood filler]. You can get it in different colors,so it will be close to what you have .
  You just mix it with water until it becomes like a pancake mix, and apply it to the crack.
It will harden and fill the crack, then you can sand it. It will take a stain so it is not noticeable very much.

I presume that the veneer that is there and has just separated due to weather, and it is still glued down.
 
Timber Mate is what  Fred Taylor uses and that is how I found out about it.
 Dan in Calgary
  
As I said, it is a grain filler and it works like no other.
 I have been doing cabinets for about 15 years , and I really like it