Does Bridge have card draw from a randomized deck? Because that's most likely the issue. I'm facing similar problems when trying to build something that plays Magic The Gathering like games reasonably competent. The combinatorics explosion and dealing with bluffing/hidden knowledge is really a tough nut to crack. My current guess is that you need something like monte carlo reinforcement learning to do it.

Forcing an Error is an especially hard case because in machine vs machine matches both sides would be aware that something could force an error and would therefore not fall for it.