Need help with MARKET

I guess it must be a simple fix, but I can't figure it out...

Somehow something changed in my game and when I hit a hotkey to buy/sell resources, doesn't buy/sell 100 resources as it always did, but now buys or sells the maximum possible amount of resources...

If I don't hit the hotkey and click in the UI button works OK. What did I changed??

I would appreciate some help with this please. Thanks in advance!