I was today years old when I tried tanking in Thaleia for the 1st time. I was the main tank & everything was going smoothly until the final boss when s/he is about to cast Hydrostasis. As usual, I went near the puddle that will inflict the 1st knockback. However, somehow I wasn't pushed to the 2nd puddle & that caught off my guard, caused me to fall to the abyss because the next puddle indeed pushed me this time & I was far away from it. It happen for the 2nd time when the boss casted Byregot's Strike. I went near the blue circle, expecting to get knockbacked, but it didn't push me at all.

Are tanks supposed to resist knockback sometimes? I've tried to look for answers but couldn't find one. And I swear I didn't activate my ARM'S LENGHT during both mechanics.

Thank you for your answers!