I got two sections apart once by taking two lengths of 1" x 1" timber that are long enough to be taped to one section, travel the entire length of the other secion and beyond, over-hanging by at least the amount of the joint.
Hold the sections vertically. You tape the pieces of wood to either side of the upper section so that when the lower section falls out it still has room to travel. The wood should stand on the floor and the carbon parts suspended about 6-8" off the floor.
Now (avec courage mon brave) smack the lengths of wood on a hard floor and the stuck section should come free and fall the extra few inches to the floor also. You can tape a little cushion, some scrumpled newspaper, to the end of the section to protect the carbon when it hits the floor.
It sometimes needs a few thumps, but the shock and the weight of the stuck section should free them.
If you email me, I'll send you some pictures of the general idea. It worked for me on a pole and on a telescopic landing net handle.