Just like any shooting position, good consistent technique has to be used with a light rifle or it’s not hard to get a poi shift, usually lower if too much preload is used, or higher if the legs hop on a hard surface. It’s no different from shooting over a pack and getting poi changes from putting more shoulder pressure on the stock, or resting the forend directly on a hard surface.
What that good technique is also depends somewhat on the construction of the tripod. Most hunting rifles will recoil 1/4” to 3/8” before the bullet leaves the barrel - whatever the bipod does during that distance is transferred to the stock. My Harris models have stiff vertical legs and on a hard surface it seems to open up groups 1/2 moa vertically, but on soft dirt there’s no change - in my case it has nothing to do with the forend contacting the barrel. Other makes and models have much more forgiving designs and shooters can be much mess careful about preventing hop. Many people put a little forward load on the legs, and that allows a little more rifle movement before the feet on the legs move.
Simply shoot with and without the bipod to test your technique. I think of the surface that is being shot off of and pad it slightly if hop is likely.
I have have no idea why, but two very similar rifles can react differently to bipods - maybe it’s forend stiffness, or something else. Every couple years I give bipods another try and usually go back to shooting off a pack.
