Command Block Bugs

I was making an adventure map when I noticed that commands that used to work perfectly fine just suddenly stopped working. I click a button for example and it should give me a set amount of items as it usually does, but they just don't work. To make sure that the commands are working and I didn't mess up, I look and the output said the command was indeed successful. I have to end up breaking the command block and link another longer trail of redstone to make it work properly and I keep having to do it and it's getting on my nerves. I'm not really sure why this is happening but PLEASE FIX IT.