Honestly you should've known the nerf to the santa boxes was coming, I don't understand why it wasn't capped at 30 coins though.This is the big problem. The big, flashing-red-lights problem is that they "forget" about one source of coins, as you said, and then they slap a limit on there after people have been able to buy out the entire shop. But the bigger problem THIS time around, is the fact that not only do we suffer through a week of unplayable levels of server lag, but we then lose our CM for no rightly-explained reason and we get what I can only call a knee-jerk reaction cap placed on the coins we can gain.
What I'm more upset about is that this happens with literally almost every coin shop we get. There is always a source of coins that Nexon didn't even pause to think about, so its uncapped. Allowing a few people with no life to gather enough coins to buy out the shop on what is actually an exploit (considering it is always, always patched), while then turning around and saying "Nope, f**k the rest of you, you have to grind your life out to get as many coins over the next few weeks that these guys got in a few hours."
No rollbacks ever come anymore to stop like this. No measures are ever taken beforehand to ensure it doesn't happen again and again and again. Never. Nexon doesn't seem to actually care. If they did we wouldn't face this problem with every single coin shop. If they did we would be getting rollbacks when it did happen so that no one would get an unfair advantage in this game due to having been able to devote dozens of hours to farming coins before whatever limit was forgotten about is implemented in a hotfix.