When tinker learns enginering upgrade, the demolish spell upgrades with it, but when you transform on robo-goblin, then back to normal, and robo-goblin again, the demolish gets back to level 2, dealing only 2 times normal damage on buildings.
The problem is dumber even than that. Reforged release split apart the concept of Ability in the game and broke it. They have Ability Skin and also Ability Code.
In your example, Reforged stupidity is breaking the Skin of the Demolish but not the code. So the damage it deals is still correct, but the tooltip and displays are retarded on Reforged. We asked the previous team to fix this on Patch 1.33 and in response they kept the stupidity of Reforged adding Ability Skin but shot up the game with addition conditional “if” branches so that learning Engineering Upgrade will change the demolish Ability Skin if the unit has demolish. Of course, as you stated, this has the stupid consequence of demolish entirely resetting to its old incorrect Ability Skin if the ability is gained and lost, which happens whenever RoboGoblin is toggled.
I applied to this company hoping to save the game code because I am a Senior Software Developer and could have done their Senior Software Engineer role to maintain the WC3R tech stack. I did not even receive a phone interview or any human communication. I find it possible that they are not interested in maintaining Warcraft 3 game system in a serious way. Maybe someone at the company will fix this bug during their lunch break since they wouldn’t be allowed to normally touch this game’s code. But there’s probably so much red tape and stupid bureaucracy that no one would be allowed to think clearly enough to actually delete the stupid Ability Skin concept back out of the game.
P.S.: To those who read this post and say that I sound like an unprofessional guy and of course no one would hire me, I am going to respond to you inevitable haters in advance: I have been using and modding Warcraft 3 for 20 years, and it makes me feel old. I like the game and technology and take my job seriously in life. I would like to believe you can appreciate that my slightly colorful remarks when faced with this game’s decline – as a fan and not a professional – are the result of emotional involvement with the technology, and in serious professional work environments could be contained or trained out of me. I just wanted to express myself. Sometimes I wish things were not as they are for Reforged. If you do not appreciate that, you are free to take the alternative stance that Activision is actually really good at recruiting and does not want to get involved in the hiring process with someone so passionate, because caring about the game might be bad for business. That’s another logically sound possibility in my mind.