If LabVIEW loads VIs or SubVIs generated by an elder version of LabVIEW, it automatically recompiles the code - even if you dont run the vi.
This results in a change of the compiled portion of the code - the portion of code that is running when you start the VI. That is why LabVIE is detecting changes in the vi even though you did not do anything yourself.
There is one thing you can do: use the masscompilation to update a whole directory of VIs. You find this option in the menu tools-> advanced -> masscompile. Depending on the number of VIs this will take some time, because every VI has to be loaded, recompiled and saved. Mind that afterwards you wont be able to open the VIs with elder LabVIEW versions.
Ingo Schumacher
Systems Engineering Manager CEERNational Instruments Germany