Why do I receive damage through Protective Spirit and Stoneflesh Armor

Hello!

I was playing around solo farming Kappas outside of Gyala Hatchery. I use PS and SA to become immune to damage. However sometimes, damage comes through and I can't figure out why.

Why do I get the damage and is there an option to negate this damage?

Here is a low quality .gif (due to .mp4 attachment restrictions) of the video feed:

Thanks in advance

Oh ok, it works for me on Firefox, both on desktop and mobile.

I do apply PS berfore SA. It seems so random.