Strange CFrame behaviour

Please, someone…
Help me here been sitting with this problem for hours.
So, what I’m doing is welding this model onto the characters humanoidrootpart as part of a slash effect.
In order to keep the models/primary parts CFrame I choose to invert the C0 and C1 which makes the CFrame stay as intended. However, whenever I try to rotate the weld.C1 instead of rotating the part instead goes in a direction depending on what axis I am trying to rotate on. I have come to the conclusion that is has to do with the Inversing of the C0 and C1 which sadly is necessary for me unless someone else has another solution to either keeping or setting the CFrame to a part that is welded. I can show code if necessary.

Either C0 or C1 has some offset position in it. Try printing C0.Position or C1.Position.