I have a LPC4337-based project. Debug builds always run from a power-on-reset. However, a release build may only boot about 30% of the time, i.e. there is no evidence the code begins to run. Something else, that may be telling, is I have run release builds in the debugger and I get a hard-fault exception when a read of an address within the EEPROM area is attempted -this never occurs when debugging a debug version.
I believe all project properties are the same for both builds.