Yes, it easily can. When shooting off a hard surface with a bipod, you have to drive the rifle more and keep a firm hold to minimize the variation. There's a few things to consider, like you mentioned. You need to make sure you rifle is properly bedded and the stock is not flexing so much to cause the erratic groups. If I have a factory hunting rifle and it is unbedded and/or I get some stock flex, I will not test the accuracy with hand loads with a bipod attached. I will use sand bags front and rear. The bipod will cause the stock to flex, and change up the mating of the action to the stock, which will effect groups and/or POI. Some of the rubber coated Hogue stocks found on Remington rifles will have a HUGE stock flex in them. These are the worst to shoot with a bipod. Next, the hard surface will amplify any shooter positional issues during recoil, effecting the POI or group size. At Rifles Only, they often have the KYL (know your limits, shooting 1", 3/4", 1/2" and 1/4" dots) off the wooden deck. Same thing as a concrete hard surface. I make sure I am properly behind the rifle, have perfect trigger finger placement, and have firm pressure on the rifle to drive it straight and the rifle not to bounce up or off target during the shot. Also, when the rifle heats up and there is any pressure at the action/stock mating, you will get fliers, like you described. And if you are loading the bipod up when shooting, this will amplify any issue also.