Anything containing cysteine amino acids such as GPB or Keratin(cysteine is a component of cysteine) seem to be the problems with relaxer reversion. I do not know if this happens with no-lye relaxers, but in my experience it does happen with lye relaxers.
Though Nexxus Emergencee is a potent treatment, it does not contain cysteine or keratin. It contains collagen if I remember correctly. This may be why some can successfully use it after a relaxer treatment.
When I first started noticing that certain protein treatments used too soon after relaxing seemed linked to reversion, I theorized that adding the very protein back that the relaxer broke down was causing the reversion. I asked my stylist and she confirmed this for me and suggested waiting 2 weeks after relaxing. This time frame has worked well for me.
My theory is that since the relaxer chemical essentially bursts the hair cuticle wide open and makes it very vulnerable, that it can easily accept proteins. Though the proteins from conditioners are not the hair's natural protein, it is known that the amino acid cysteine is responsible for curl in people's hair. The more cysteine, the more curl. (Hence, we aa's have lots of cysteine in our natural hair. The relaxer chemical breaks the cysteine bond and thus straightens our hair.) Anywhoo, if the cuticle is wide open and cysteine is being added right back to the hair moments after a relaxer, I can see how this would cause reversion.
HTH