There are bugs around this for many versions now.
Sometimes in MP if you leave something constructing and then log off, the game will stop producing things in the constructor but will run as if at full power until you log back in.
Let’s say you were constructing 100 fuel packs in the constructor and logged off before it finished. It should only take a few minutes to construct all those, but sometimes the game will keep using the full power as if it’s still constructing them until you log back in.
So your 100+ hours might have been reduced to a fraction of that because of this bug.
It’s been reported quite a few times ever since they added DSL into the game. It still happens but they were never able to reproduce it at will to fix it.
I’m not saying this is for sure what happened here, but it seems highly likely based on your descriptions.