Did the game get a patch for Resources, specifically Fuel, Biological, and Common Metal? I was aware of the ability to edit them in CheatEngine by multiplying the displayed number by 2, which I toyed with a little bit a couple days ago.
Today though, I wanted to add more of the Fuel and Biological resources and couldn't get the values to work. I just tried MAF's +12 trainer, and the Minor Metal and Precious Metal both maxed out, but Fuel, Bio, and Common all stayed the same. Not quite sure what happened unless it was a weird silent patch?
EDIT: I'm not sure, but there's a possibility it depends on the Mother Base Material Deposits value. If you go into the Mother Base Management screen, the one where you choose to upgrade or build new platforms, in the lower right are 5 icons for Material Deposits.
The 3 Material types I can't edit anymore, Fuel, Bio, and Common, all have a "B" rank. The two that I can still edit, Minor and Precious Metals, have a "C" and "D" rank respectively. I'm wondering if upgrading those Material Deposit letter rankings makes it so you can't cheat in more resources?
The values still have to be stored somewhere, but something definitely changed. Try upgrading the Base Development Platform a few times and try it out. That's the platform that effects the Material Deposit ranking.