The Yamaha SSS forks are very sensitive to the bushings. Old bushings will actually start affecting performance and seal life even before the show visual wear of the teflon being worn off. If you see teflon worn off they are for sure shot.
Also, the inner damping cartridge can definitely cause the problem you have. If it is not properly bled or if one of the cartridge seals is leaking you can get a stuck-down effect. Also, the plastic free pistons are known to crack and could probably cause some binding. Bottom line, it all needs to come apart and be checked.
Powerband in every gear !