I have a broadcast network with one wireless Bridge which breaks this Network in 2 parts when it fails.

One part is a router (Router A) which has a connected interface in this Network. This router has the shortest distance to our core.
The second part has 2 Routers (B and C) within this Network.

Normaly traffic is routed through A into this Network as OSPF distance is lower. As soon as the Bridge breaks the route into this network goes through B.

All routers redistribute connected routes as type1.

So what is happening?

I'd say you get a classical splitt brain scenario where both sides tries to converge and finds them self as DR's and depending on other redistribution many blackholes in the routing.
This is why you run OSPF and perhaps you should have a backup direct link to avoid SplitBrain.
But Who am I that may or may not be doable in your situation so..... one could state that what you have now is bad network design. No Offence. Just stating the obvious.