Very basic question, but here is my continuing confusion about setting white balance versus what camera "sees" in some situations. Most of what I read about white balancing is related to studio setting where advice is to have talent hold gray card and you manually set white balance off that gray card--light reflected off gray card is same light talent is in. No confusion, I manually white balance.

However when shooting outdoor scenery, light where you are standing can be different from light hitting distant scenery. For instance, I am standing in shady location on sunny day (shady light) and shooting a distant scene that is in full sunlight. Sometimes I am constrained to shooting from that shady location (can not move to same sunlight that scenery is in to do white balance). If I do manual white balance where I am standing it seems the properties of shady light reflected off gray card and into camera (for white balancing) is different than properties of light reflected off distant sunny scenery and into camera lens. Does this difference in shady light vs full sunlight skew white balance of camera?

I have experimented a bit in controlled situation: (1) white balance in shade and film nearby sunny scene; (2) move to nearby sunny location, white balance, then back to shade and film sunny scene; (3) stand in shade , aim camera at sunny scene, give camera time to use ATW to set white balance and then lock white balance before filming. Frankly, with equipment I have I can not see noticeable difference so I am wondering what theory would say.