catch on something, obstructed, hindered
絓 centers on being caught or held back: something that snags, obstructs, or hinders movement or progress.
絓 combines 糸 (thread) with 圭, which likely contributes the sound. The idea of thread catching or snagging fits the meaning of obstruction.
Thread 糸 wrapped around a jade tablet 圭: the thread catches and snags, obstructing the smooth surface.
For カイ, imagine a kite string catching on a branch: kite -> カイ, and the thread snags, hindering the kite's flight.