Hi Vipin;
This has always been a "risky" approach when rebuilding one PBD on one library. Even in older PB releases from SAP, Sybase or even PowerSoft. Its not too bad when rebuilding a library with only "concrete" (working) level objects. However, its almost a "death sentence" (as you might be finding out) when rebuilding one PBD that contains either "Base" or "Extension" level ancestor object classes.
The problem starts or gets really accentuated when you add or remove instance variables. Internally in PB's P-Code a variable is referenced via a base address plus its offset into the object's data section. When you change that by changing the instance pool, you can inadvertently change the offset addresses of many other instance variables at the same time.
If you do not perform a "Full Build" and then redeploy your app with all your PBD's, there will be various "Concrete" level classes that have the wrong base address + offset. This will certainly lead into a GPF. So my suggestion would be to never trust one only PBD generation and instead, always perform an incremental build on all PBD's - and if in doubt - a full build (especially before a production release).
HTH
Regards ... Chris