File does not begin with %PDF- error in BI cluster environment

Hi experts,

We have BI 11.1.1.7　environment (cluster BI)

[ BI#1,BI#2,VIP(used for load balance)]

Case1.

when I shut down application deployment(analytics) on BI#1,

then access to the bipublisher on BI#2 and log-in it,

when trying to open a report, we get the "File does not begin with %PDF-" error.

Case2.

when I shut down application deployment(analytics) on BI#2,

then access to the bipublisher on BI#1 and log-in it,

when trying to open a report, it works, and there is NO "File does not begin with %PDF-" message.

Please advise how to overcome the "File does not begin with %PDF-" error.