I'm in the middle of breeding a Dragalge with Toxic Spikes and currently breeding like crazy for its offspring to have better IVs and shiny too.
When I leave the male Skrelp at caretaker together with a female it will eventually get Toxic Spikes replaced with another move which is normally what would happen.. but as long you don't take the male out of the daycare its offspring is supposed to gain the abilities from when the male was put inside the daycare even though if those move are replaced.
My solution have been to delete all other moves on the Skrelp than Toxic Spike and check on it now and then if it learns other new moves so I can delete them before they end up replacing Toxic Spikes.
It's not a big problem at all, but now you can be aware that it acts different than the retail games
Btw is there anywhere to find a Destiny Knot in Reborn?