sample changes on existing project

Sorry, I have seen this posted many times when I search but I do not seem to see a clear answer why this happens.

I use Cubase LE7 with Focusrite Scarlett Studio, with the same hardware setup since I started using it. My default Project Sample rate is always 44.1 KHz and at 24 bit resolution. All projects are saved in 44.1KHz - 24 bit. These projects contains MIDI and wave audio samples all set and saved at these rates. So, there is no reason at all for a project to change frequency or resolution of the sample rate. I use only one desktop PC with Windows 8.1 and work from the same hardware and the exact same setup each and every time.

However, on occasions such as today, for no reason, I open an existing project and up in bright yellow on the status line it displays Record Format 48 KHz - 16 Bit.

Are the sample rate settings saved with the project?
What could possibly cause Cubase to change the sample rate settings on an existing project, especially when they are never changed to anything else?

I can only assume something interferes with the software or causes it to change as my hardware setup has not changed at all since the creation of my projects.

Please help.