I noticed a similar problem with startup on the LM2776. I have a nice hot-swap circuit on the input that ramps VIN from 0 to 5 V over 2.5 ms, and yes the part fails to start with all the recommended components from the datasheet and EN tied high. I was able to workaround by adding a schottky diode on VOUT. It seems that without this external schottky, if it is powering +/- 5 V op-amps, then the -5 V VOUT gets pulled to a diode drop above ground. This in turn causes a substrate current to flow, which ends up disabling the device and it latches off.