So are you saying that the same problem occurs when you put BPS in Default Mode? BPS does not do anything with cookies.
“BPS is stuck in the past and holding on to nonexistence old information.” – not possible. BPS always works in the present and is not capable of doing something like that. If you put BPS is Default Mode then BPS is no longer a factor in the equation – Default Mode means BPS is Off. BulletProof Mode means BPS is On – there is no inbetween – there is only On or Off.
What I recommend you do is go through all the changes you made and make sure that you have put everything back the way it was and then if you are using other plugins that do something with cookies then take a look at those plugins – BPS does not do anything with cookies.
If you have a caching plugin clear your plugin cache, etc.