I skimmed your previous posts, and it seems like you have a question that's best suited for either the general residency forum or the OBGYN forum.
FMGs have an uphill battle to obtain a spot, and the places that tend to accept FMGs like you (who struggled for several years to obtain a spot) often are the same places that tend to chew through them, fire them, replace them with new ones, etc.
The two main reasons to go on probation are 1) Clinical underperformance and 2) Professionalism issues (lying, fighting, laziness, emotional instability, etc). You should find out if it's one or both of those, and be sure to look internally and accept that it may be partially true. If you are defensive and blaming the system, etc, then the PD will decide you're "unteachable" and unaccepting of your faults, and will eventually fire you.
It is normal to "build a case" against a resident who is on probation. If there's a chance that a resident will be fired, there needs to be a paper trail, otherwise there's risk of litigation.
Yes, you should find out the process and make sure it's followed....but most of your energy should be concentrated on fixing whatever problem your program thinks you have. If you give us specifics, then we can help a bit more. However, if there was some isolated incident that led to probation, and the incident is over now, I'd focus on not letting something similar happen in the future.