Full suspension bike or hardtail?
Check the length of your housing from the shifters to the first frame cable stop. If the loop is too short it can cause ghost shifting.
Also if you have full suspension, the piece of housing from the front half of the bike to the bike half might be too short and when your bike cycles through it's suspension travel it could cause a lot of cable tension. (this could explain the 'after climbing' where you compress the rear suspension).
Another place to look is the loop from the cable stop at the frame to the derailleur. Again, too short and it could ghost shift.
If your shifting in smooth in part of your range, but not in the other. i.e., smooth shifts in the higher gears and crap shifts in the lower gears, that is usually and indication of a bent derailleur hanger.
__________________
"Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming, "WOW, What a Ride!" - unknown
"Your Bike Sucks" - Sky Yaeger