Colokeb...
I no longer remember the specific problems associated with the Model 39 but Smith did come out with the 39-2 to correct some of the initial faults. I don't recall if the same issues plagued the Model 59 and I would defer to anyone having experience with the model.
Regarding feeding issues, the first JHPs offered for semi-autos often had exposed lead tips, just like revolver ammunition. Lead has a high coefficient of friction and feeding issues were common in all semi-autos. This caused, first gunsmiths, then manufacturers, to pay more attention to the feed ramp, either polishing, or re-contouring it a bit. Eventually, JHPs intended for semi-autos and with exposed lead contacting the feed ramp slowly faded from the scene.