Is anybody else having trouble using some transferred Pokémon online?

[Rancid Sunset]

I recently transferred my Shiny Mawile and was going to give it to my Sister as a Gift But when I try to trade it to her it gives me an Error saying that there is something wrong with the Pokemon I know for sure this is a real one hundred percent Shiny Mawile since It took me two weeks to hatch it and here I am Not being able to trade it or even use it in online battles the same thing happened to a Girafarig from Emerald Safari Zone.

Is anyone else having similar problems?

Update:I changed one of My Shiny mawiles move with a TM and now it's able to be traded to my sister so I guess Poketransfer has some few stuff to workout

[auroraborealis]

Something similar happened, I had some rareball good-Iv pokes that I bred myself in alpha sapphire. I transferred them into sun to wonder trade and while some of them were fine, it wouldn't let me trade any ralts or poochyenas because "there is a problem with the pokemon"
Maybe I'll try changing their moves and see if that works.

[S.A. Natsu]

I was trading last night and my 20th anniversary Keldeo wouldn't trade and neither would the other guy's 20th anniversary manaphy but zekrom and Mewtwo traded just fine. Weird

[Rancid Sunset]

I'm relieved now that I wasn't the only one having this problem I actually thought something went horribly wrong during the transfer but it now puts Me at ease knowing I wasn't the only one with this issue.

[auroraborealis]

I forgot about this but I actually tried again, and I was randomly able to successfully trade the ones I was having problems with without making any changes. Maybe there was some issue that they've resolved? Idk.

[nokuto]

Wait, so in other words certain movesets are the issue? I heard there's some new attacks and all, maybe they didn't update that or something. I think for Sun/Moon, they update the eggmove list so maybe.. >3>; not sure.

[Rancid Sunset]

Wait, so in other words certain movesets are the issue? I heard there's some new attacks and all, maybe they didn't update that or something. I think for Sun/Moon, they update the eggmove list so maybe.. >3>; not sure.

That sounds more likely after all there are bound to be a few bugs when something new comes out it isn't always perfect so I guess the issue was Hotfixed over night.

[UltraSound]

^I forgot where, but I watched an in-depth analysis video on what happens for the pokemon that get transferred. There's some really weird algorithm choices they've made that may accidentally make the pokemon seem illegit. (ex. of weird algorithm; exp/level affects the gender (or nature, I forgot), ATK and DEF IV's are read backwards, resulting in pokemon potentially losing their shininess during transferring, etc.) I'm not sure if they've been patched yet though as I haven't used the transferring function.

[trainerj96]

I had issues with a few pokemon that were move related as well