That is an odd issue! If it actually runs fine after restarting, the only thing I can think of, and this is a shot in the dark, is the ignition switch, or the adjustment of the ignition switch rod in the steering column.
POSSIBLY when you shift from drive to reverse the linkage to the ignition switch is being activated(the rod from the key cylinder to the ignition switch) maybe you could try adjusting the switch see if it affects the issue? Does your car have a tilt Column? And if so is there alot of slop in the tilt mechanism?
When I put the tilt Column in my 78 the column had alot of slop because the U-joint mounting bolts had come loose, and it caused issues with the ignition lock not actuating the rod. Also just did not feel secure when driving. I had to tighten up and lock tight the 4 U-joint bolts to cure this issue and make it feel right when driving.
Good Luck with it. And if you find the issue let us know what it is please!!!