Sometime i cant upgrade factories to T3
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Also i noticed that T2 engies can build T2land factories right of the bat
That was not in the base game right? -
There are support factories and HQ factories. Support factories are significantly cheaper than HQ factories, have the same production ratings but they are weaker in defense. You need to have a T2 HQ in order to make a T2 support factory. Once you have an HQ of a given tech, an engineer of that same tech or higher can right away build a support factory
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To add to what Jip said, it looks like you are trying to upgrade a support factory to t3; you first need to reach the relevant teach tier on your HQ factory, afterwards, you'll be able to build/upgrade the support factories.