Constraints Ignored and Dimensions Changed When Re-opening Assembly

[kvp1]

We have been working on a pretty complicated and important assembly. As we have worked on it we have saved the file and checked it into the vault. As we have worked on this project since we have had the vault we have noticed that the file will change itself when we re-open it. When we save and close the file (trusting that it will keep our changes) and then re-open it the assembly will "update" and many things will be different. Constraints will be ignored, dimensions will change and some very critical aspects of the file will be different. I have had to go back in and fix this particular assembly several times because of these random changes.

Production of the physical assembly in our shop is almost over and we need to finalize all our drawings and save them for future reference. I want to be confident that whatever we save is correct and will not change unless I change it. If things change every time we open the drawing it scares me to wonder if we can trust anything that we have drawn.

If anyoe can help, please let me know.

[mdavis22569]

So is it the dimensions and 2d drawings that are changing or the 3d model and it's changing the 2d?

Can you give a ref example to look at?   

Even images of say what it looks like before you check it in, and then after you check it out and it "changes/updates"