getting process error a!fromJson: Invalid index: Cannot index property 'body' of type Text into type Text) (Logic Output) in appian

Hi

Process was getting errored saying the error like a!fromJson: Invalid index: Cannot index property 'body' of type Text into type Text) (Logic Output) in appian in the output of node passing the logic like below 

tointeger(
index(
a!fromJson(
it was integration:rule!UIP_GetQueueItemBy(
OrgsUnitId: 100,
reference: ri!reference (type of rule input reference is text)
).result.body
),
"@odata.count"
)
) > 0

Kindly suggest on this for some instances it was working well for some it was erroring like above