Rubi just announced some changes that will go live when SotO is released. Apparently ArenaNet doubles down on disabling core mechanics (dodge or block to avoid damage) in this Fractal. (Being able to block Frightening Speed was a bug.)

https://en-forum.guildwars2.com/topic/134453-updates-coming-to-silent-surf-august-22/#comment-1951064

Hi all, I want to let you know that we've been reading your feedback about Silent Surf and have some updates incoming.

As you can imagine we are all heads down on the final stretch before Secrets of the Obscure launches on August 22--only four more weeks! Our next full build is scheduled to ship then, so we'll include these updates with that.

For now though, I have an early look at the update notes for Silent Surf so you can see what the team is working on:

Bug Fixes

• Fixed an issue that caused Captain Thess to have an incorrect effect icon during the third encounter.
• Fixed an issue that prevented Aspects from applying Extreme Vulnerability on Challenge mode when striking with Dread Visage.
• Fixed an issue that allowed players to bypass World Cleaver.
• Fixed an issue that could cause the final boss to focus on attacking pets more than intended.
• Fixed an issue in which the Peace and Quiet achievement did not require Master tier, causing it to be inconsistent with the achievement description. -Fixed an inconsistency with other Challenge mode encounters in fractals so defeated players can now be revived during the final encounter.
• Fixed an issue that allowed Frightening Speed to be blocked.
• Fixed a timing issue in the Challenge mode version of Dread Visage's large-eye warning effect that prevented it from detonating at the same time as the smaller eyes.
• Fixed an issue that could cause an Aspect to return to the main platform during World Cleaver without selecting a new target for Phantasmagoria.
• Fixed multiple issues with phase transitions and the synchronization of Dread Visage attacks:
  • The final boss and the Aspects no longer gain alacrity, regeneration, or quickness from boon-stealing attacks.
  • Sugar Rush has been removed from the list of Mistlock Instabilities for Silent Surf.

Other Updates

• The final boss's health has been reduced on Challenge mode.
• All checkpoints now require only two players regardless of fractal tier.
• In addition to Sugar Rush, the following instabilities have been removed from Silent Surf: Mists Convergence and Toxic Sickness.

As always, thanks for your constructive feedback and keep it coming!