Many have had issues and several have a little set of tips for in game saving such as not saving near a base or not saving under water and some will advise more. It really seems to depend on nothing and seems to affect people at random and seems to be caused by some of the littlest things though.

Welcome Aboard Hammermill :salute:

I'd seriously advise you not to save whilst submerged or within a radius of approx. 50km of anything that is rendered in game such as vessels, aircraft or a land mass.