This is a pretty weird problem and doesn't make sense at all.

My Front derailleur shifts fine when the bike is hung up on my work stand. When I stick it on a trainer or take it out to ride the FD won't shift into the big ring very well. It takes an extra amount of force to get the shift lever to click into the next gear. Most of the time it just clicks, makes the chain rub the derailleur and doesn't actually go into the big gear. I adjusted all the limits and cable tension properly.

Again, this only happens when there's resistance on the rear wheel. It works just fine when it's on the repair stand and the rear wheel is spinning freely with no resistance.

Any ideas?