Yes this appears to be true with the Motley !
No this is mostly only applied to the Motley at this point not other Boa mutations.
Although some other CoDominant Boa Mutations show some signs of slight problems.
The Motley is a CoDominant trait CoDominance therefore the wild type (normal)looks different
than the Heterozygous or homozygous forms. The Heterozygous form
also looks different than the Homozygous form.
We do not know why yet but there are many discussions about why or what causes
Super Motley's (Homozygous form) not to survive past 2 years of age.
The Homozygous Motley form contains 2 mutant Motley alleles, from discussions possibly this is
a lethal combination programed into the genetic system.
There are other similar combination's from other species that behave in a similar fashion.
People are doing there best to understand these phenomena.
I can't pretend to fully understand genetics entirely, it's way over my head . 
Although I can gain a simple understanding of the basic ideas
behind genetics and how it applies to the animals
( Boa Morphs) I enjoy working with 
. . . Lar M
My best advice read as much info about Mendelian genetics as you can find 
Click the below link
Mendelian Genetics
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Boas By Klevitz

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