Now, I'm not completely sure about this, but I think I can explain why this happened. On the text for Eevee's (SUM) Energy Evolution Ability, it says...
"When you attach a basic energy card from your hand to this Pokémon, you may search your deck for a card that evolved from this Pokémon that is the same type as that Energy card and put it onto this Pokémon. (This counts as evolving this Pokémon.) Shuffle you deck afterward"
... the text that is in bold is the problem I believe. Once Eevee searches for the evolution, the ability isn't finished as it becomes a new Pokémon (in this case an Espeon GX) and then has to shuffle the deck. When Eevee evolved, it became the GX which means Eevee's ability is now Espeon GX's ability since Eevee isn't part of the field anymore. This means that Glaceon GX's ability shuts down that one part of the ability, and if you can't finish all of the ability, then you can't reach the final outcome. Now this is just my theory, but it is the only possible way that I can think of besides just an malfunction on PTCGO this can happen. Hope this helps!