Diminishing returns and their duration explained:
1st stun: 4 sec duration. 50 sec later stun: 2 sec duration. 50 sec later stun: 1 sec duration. 50 sec later stun: stun resisted. 10 sec later stun: 4 sec duration.
Stunlocking in a row: 4 sec - 2 sec - 1 sec. 30 sec later: stun resisted. 30 more sec later: 4-2-1 again.
Silence doesnt have diminishing returns.