There was recently a stealth update that nerfed achievements. Now certain achievements like pioneer and cannonball take a SH level in order to do, and the levels required are very high (High 20s, to 30s SH level)

You can't just let players spam achievements for gold and then take them away from everyone else. This creates an extremely unfair balance between people who rushed and did everything at low level, and people who didn't. Those players got HUNDREDS of millions of free gold without having the new "required" levels and now everyone else cant do the same meaning those players and clans have a massive advantage. 

This is an extremely bad practice to do as a game developer, you cannon just slap the face of half your playerbase like that by releasing such an overpowered broken system like achievements then just yank them away from everyone who didn't have a chance to benefit yet while still leaving all the players who did to keep their hoards of free stuff.