I think more likely to happen when the similar marking/color and size of Corys are kept together. For example, Dividsandsi, Melini, Matae and Panda. Or all the so called spotted Corys, they would more likely to hybrid among similar spotted Corys.
Then again, not long ago, someone was posting the picture of hybrid between Panda and Sterbai. And she said she had enough males and females of both species in the tank. So I guess you never know which different species of Corys would hybrid.
Also make me wonder if it could happen accidentally when both species spawning with their own specie but wrong sperm happen to fertilize the egg(s) of the other specie just because they spawn in the water.
Anyhow, I think it would be better off if you can keep the each species in the different tanks if it is possible. Especially if you are planning to breed them. Or do not save any eggs you find in the commnity tank if you have too many kind of different Corys in it.
And if you still end up with some offspring that have any possibility of hybrid, you should not release to the general public. This is of course just my opinion. And I know the hybrid and some extreme selective breeding to create the new looking fish is always a big debate which I am not try to do here.
The hybrid of Corys is like hybrid of dog and wolf, if there is no desirable opposite sex is not present they will mate something similar so they will not extinct. So the most Corys if not all Corys will definitaly hybrid if the situation is called for. I think they will even mate with another species if none of their females is not ready to mate and another species' female is happened to be ready to mate. I don't think this would happen often but it is still possible.
So I would say please be careful if you are keeping different Corys in the same tank and planning to save the spawns. But if you are serious about breeding certain Cory, you should use species only breeding tank anyway.
I'm sure not all the people would agree with me but I am not try to initiate the debate here. Like I said before this is just my humble opinion.