This probably relates to the other spectator-related hitbox bugs (MC-279016, MC-279021, MC-279031, MC-279032, MC-279033).
Steps to reproduce:
Place a cobweb.
Enter spectator mode and turn your flying speed up to the maximum.
Fly through the cobweb.
Enter survival mode.
❌ "<Player> moved wrongly!" warning gets outputted in the console (might not always happen).
Can confirm.