Engineering Upgrade problem

I've been working with the new EU ability of the Tinkerer, using it in a map of mine to act as a Skeletal Mastery for a Raise Dead skill.

I've made it for 5 levels, but for some odd reason once i get it to level 3, it turns into another skill without any icon or text. Is this some kind of bug, or do you think there is there some kind of mix-up in my triggers somewhere?

This happened to me not long ago - I solved it by filling in *all* of the possible level data for the ability upgrades; just make them the same thing as the first filled in spot of the Ability Upgrade 1 levels.

Problem solved.

Thank you very much.