Can't build support fac with (A/S)CU , can with engi

[E8400-CV]

I played an Ozone earlier today and at some point my dinner was ready and I gave everything, minus ACU, one SCU and SMD to another player. Later on, that player died and all was transferred to the 3rd player. When I returned, he gave me back my base plus that of the guy that died. My old base needed a huge expansion , but even though I had a T3 air HQ, I couldn't build T3 support facs with the SCU or ACU. But with T3 engies I could

[Aurion]

I played an Ozone earlier today and at some point my dinner was ready and I gave everything, minus ACU, one SCU and SMD to another player. Later on, that player died and all was transferred to the 3rd player. When I returned, he gave me back my base plus that of the guy that died. My old base needed a huge expansion , but even though I had a T3 air HQ, I couldn't build T3 support facs with the SCU or ACU. But with T3 engies I could

I assume everything (HQ, sACU/ACU and engineers) were of the same faction? If not, there's your problem.

[E8400-CV]

Yes, all same faction.