If you upgraded both the client and server to 188.8.131.52, none of the old change notification bugs should be there (11808442, 10065474).
There's a bug in 184.108.40.206 (18069379) that produces a "FAILURE: Registration notification error". To be able to identify if this is a known issue, can you provide details on what part of change notification fails (i.e. notification registration on server; no notification sent upon change; listener does not come up; port does not open; etc.)? Any error codes that come up will be helpful.
No Notification is sent once I make a change to the table in question.
I can't seem to find anything on the BUG you've listed above. Do you have a link to it so that I can read more on it? After troubleshooting this for several days now I am no closer to figuring out what is going wrong. No errors seem to be generated (well... none that I see). Is there somewhere else I should be looking for error messages? A certain log file perhaps that I am not aware of?
The bug I listed is unlikely to be the problem source since you have different symptoms. Moreover, the bugs I listed were ones originating from ODP.NET or Oracle Client components. However, it sounds like it's the DB that is producing the error since a server change occurs, but no notification message is sent.
With no error message, diagnosing becomes harder, but usually the DB server captures something, especially when the problem originates there. Is there anything in the DB logs that indicate an error or problem? You will likely have better luck getting this question answered on an Oracle DB discussion forum since this sounds like a generic DB server issue. Or you can file a service request with an Oracle Support to research.