It aint broke yet so lets see !
The surest way is probably reduce the draw weight !
Otherwise take the riser of and build a new one, use thin strips of wood less than an 1/8 in thick to build it back up and start with the first strip being longer than the original riser !
One other trick is to use a glue soaked cordage to wrap the riser section , wrap it tight and as it dries it will shrink and bind !
I hope it works out for you!!
From now on make sure you get a main section of riser that is thicker and fades more gently, before you add more wood to it that will eliminate the problem to start with !