Display Optimized SQL is not working properly.

Hello All,

I am having a DF, in which the source is a ECC custom extractor and I am using the where condition as shown below,

Since this extractor is not working properly, I thought to see the option 'Display Optimized SQL' and it showed up one time like this,

And after some time, when I log out and log in again, it is showing as empty with out any where condition as shown below,

Any idea/reason for this strange behaviour of BODS? BTW, I am using 4.2 version on Windows server.