Is it normal?

Originally Posted by Fifi

When no stabilized view option TICKED, my periscope view is unstable while the bino/UZO is stable.
It seems it’s inverted! (Must be in rough sea to fully test)

I believe this is just how SH3 is. Binos and UZO are stable even if the "no stabilized view" is ticked. It's not inverted, the mentioned are just not affected by the option.

Bug or not, you can justify it by taking your character as a seasoned seaman who can counter the rocking action by the waves with his smooth hips