TL;DR: Exclusion mutations don't work.
I pointed this out yesterday, on my very first run using exclusion mutations, my weapon dropped with 2 of the 4 perks I excluded. It has since happened almost every time I've done it, so I recorded my latest attempt for proof:
https://www.youtube.com/watch?v=FagM59Ln4Go
If you don't want to watch, I used one mutation to 'exclude' Pulse Monitor and Moving Target, while it included Firmly Planted, Killing Wind, No Distractions and Outlaw.
I used another mutation to 'exclude' Kill-Clip and High Impact Reserves, while it included Quickdraw, One For All, Demolitionist and Bonus Super.
The resulting weapon dropped with Pulse Monitor and Unrelenting. One of the perks I excluded was on the gun, the second perk was one I did not 'include' in any of the mutations.
The mutations say nothing of chance. It simply says it 'will exclude', which it clearly does not.
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