[BirdWatcher]

I feel like part of the reason you aren't getting responses here to your various posts essentially asking the same questions is that it is hard to understand what you are really asking.

It feels like you are confusing ratings with scouting reports about ratings. What you see, if you have scouting enabled, is merely what your scouting staff (or the OSA) thinks is true of the players abilities in various areas. And yes that is a dynamic system and what ratings you will see through your scouts and the OSA scouting reports are not static and do change on a regular basis depending upon a great many factors. This is why it is imperative that you hire as talented a head scout as you can and why it very much matters what the current scouting accuracy is also.
These changes do not necessarily mean that anything in the behind-the-curtains ratings has changed for a player (which you can see by going into the editor in commissioner mode). It might (as talked about previously there are factors like random talent changes, aging, injury, etc.) but this is where the fog of war comes into the game. You are getting approximations, not the actual, exact ratings.
Assuming you are using scouting, which it sounds like you are.
Given your concerns and confusions, I have to wonder why you don't just turn off scouting altogether. (Not that I'm advocating for that- to me it is a big part of the fun of the game. It just feels like it doesn't meet your particular needs or desires.)

As for ratings changing just because you have exited the game and then re-entered (assuming you mean that no time has passed in terms of your saves calendar), well, no that shouldn't happen. My best guess is that this is just a case of the scouting ratings toggling between OSA and your team's scouting staff, but I don't know why closing and re-opening the game would cause that to happen. Are you sure that you are not just looking at ratings from a different perspective each time? Otherwise, perhaps there is some problem with your save.

We also can't know what settings you are using for things like Player Evaluation AI Settings and Player Development Settings (which includes Talent Change Randomness). So it is hard to give you specific answers about these complex parts of the game that can vary so much depending upon the game settings you use.

Can you help us to understand better what it is you are struggling with here? (Mostly by giving us better information, likely including screen shots of your settings or also of what you see when you exit the game and then how that has changed when you re-enter the same save later.)