Postgres process invoking exit resulting in sh-QUIT core

Hi,

We are using Postgres version 9.3.14 over linux based OS and we are observing sh-QUIT core files randomly when we are restarting the system(occurrence seen once in 30 times).
Backtrace is showing as below:

Loaded symbols for /lib64/ld.so.1
Core was generated by `sh -c exit 1'.
Program terminated with signal 3, Quit.
#0 0x0000005559ed78f0 in do_lookup_x () from /lib64/ld.so.1
(gdb) bt
#0 0x0000005559ed78f0 in do_lookup_x () from /lib64/ld.so.1
#1 0x0000005559ed7b88 in _dl_lookup_symbol_x () from /lib64/ld.so.1
#2 0x0000005559ed916c in _dl_relocate_object () from /lib64/ld.so.1
#3 0x0000005559ed0b6c in dl_main () from /lib64/ld.so.1
#4 0x0000005559ee5214 in _dl_sysdep_start () from /lib64/ld.so.1
#5 0x0000005559ece1b0 in _dl_start_final () from /lib64/ld.so.1
#6 0x0000005559ece3f0 in _dl_start () from /lib64/ld.so.1
#7 0x0000005559ecdc10 in __start () from /lib64/ld.so.1
Backtrace stopped: frame did not save the PC

When we checked the process listing during the time of core generation, we found Postgres startup process is invoking "sh -c exit 1":
4518 9249 0.1 0.0 155964 2036 ? Ss 15:05 0:00 postgres: startup process waiting for 0000000100000000000002EB
4518 10288 0.0 0.0 3600 508 ? S 15:11 0:00 \_ sh -c exit 1

We tried disabling DB and running the same testcase which didn't result in core being generated.
Also we are using immediate shutdown mode which uses SIGQUIT.

Can you please help us in debugging the issue ?

Regards,
Sandhya