This isn't a problem, I just noticed they're back up and I wondered what changes have been made.

Some safety precautions to prevent further farming. The exact details really don't need to be disclosed. (Nor do I know them.)

I just asked Erth in game (thinking he may know) and he said he wasn't sure but he thinks there may be a daily earnings limit and protection against DOS.

Could be. Either way it was just something to help prevent the farming exploits.

Adding on to this, certain limitations were added to the tournament servers to prevent farming.

If you have any further questions relating to the specifics of what was added, read this post again.