After you select an option for a land plot's production, there should be a step asking you to confirm said selection before it is implemented. Given we cannot reset it for 24 hours after a change, this will ensure mistakes are not immediately acted upon.
That’s a good idea, I like that.
And further on this issue, it should not be possible to reallocate the same type of production for a plot of land. I had land mining $TLRPG and wanted to change it to bronze; I wasn't paying attention and accidentally clicked on the $TLRPG Mines tile. The "change" was accepted, 10 energy was deducted (I assume, I didn't pay attention to make sure but it makes sense that it was), and I got locked out from changing it to what I really wanted for 24 hours.