Please excuse my lengthy post seeing as it is only my second post on the Sand Trap, but I find this discussion very interesting.
When I used to play previously in the late 80s/early 90s, I was a consistent 18 handicap. I then had to stop playing for around 20 years due to circumstances.
Since starting to play again 2 years ago I have been unable to get my handicap below 36 according to the Handicaps Network Africa. During the 2 years I have only shot lower than 110 on 3 occasions, and they were still more than 100.
I was going regularly to the driving range, so eventually I went to a reputable instructor in our area for 1 lesson during which certain aspects of my address were corrected and I was also not following through completely with my swing. After that lesson I was told to go practice and play some rounds and come back in a few months for a check up.
About a month later I went back for a lesson to work on my chipping which was also letting me down. After 5 minutes I was chipping much better, and was then moved to other positions around the green, including chipping over a bunker.
My instructor asked me to remind her what my handicap was and I said 36. She said, no really. I repeated what my handicap was. She said that watching me on the driving range and during the chipping lesson I should be about a 13.
So, when on the driving range and practicing my chipping it is great, but I can't seem to carry that onto the golf course.
I have read that this is quite common due to various reasons, but I have often wondered if I would perhaps benefit from a lesson on the golf course during a round.