When I went into a forum topic I got a notification window telling me I'd found something. I've now got a Spectrum Vesnali Egg without an image in my inventory. It's labelled a staff item. (I've locked it to keep it safe until I hear somete hing.)

PS: Somebody else made a topic about a mysterious egg while I was posting mine. There's an explanation about it being part of the Vesnali plot so please ignore this.

They are working on fixing the eggs. They are part of the new vesnali event so you are fine to have it!

[edit] this is fixed