Answer:
Releases for warping are at each member end by default. Splitting members leads to a warping release.
If you do not want to have a warping release there, but rather continuous warping, you need to define a member set. When activating the "Torsional Warping" add-on, the warping is transferred automatically. If this is not desired for the member set, select the "Discontinuous torsional warping" option; see the image.