It's been a while since I tried to dive into all this. My recollection is that they abandoned the initial explanation and just went with something vague about the building being in poor repair.

The official explanations also don't account for the reports about how the building was expected to collapse soon. Those started long before it actually fell. They never, as far as I know, revealed why it was expected to collapse.

Undisciplined

I think they had SOME kind of explanation for the third building going down. And I remember being a little bit confused and wondering, but basically not thinking about it too much.

Maybe that's where I could start. 

Signal312

conspiracy

Talk to me about 9/11 - what really happened

And still no explanation. That's the one that really triggers normies if you bring it up, because they have no answer, but also know that you're the crazy one.