Nothing… Although not enough enemies to keep the chain going, or finding them all on a night mission can be a problem 
To be fair this is a step in the right direction, and the idea was that all the other changes put together would somehow prevent TBs from happening.
The effort fell short, but the intention to remove TBs is still there.
However, there is a lot of concern with nerfing too much and making changes that make game systems harder to understand, particularly for new players. See here Phoenix Point v. Cthulhu 1.6 - 30th of July - #108 by VOLAND