Why I got 141 from PIPESTATUS using certain command line pipe ?

Issue

• Why I got 141 from PIPESTATUS using certain command line pipe ?

The user tried to get status code of certain command using PIPESTATUS array , and got strange return code.

aaa=`{ find . | head -1 ; echo ${PIPESTATUS[0]} ${PIPESTATUS[1]} ;  }`
echo $aaa

They expected that both of ${PIPESTATUS[0]} and ${PIPESTATUS[1]} will return 0.
But they found that sometimes, ${PIPESTATUS[0]} return strange return code 141.

]$ aaa=`{ find . | head -1 ; echo ${PIPESTATUS[0]} ${PIPESTATUS[1]} ;  }`
]$ echo $aaa
. 141 0

Why 'find .' returns code 141 ?