TimeStamp field not working for generic delta

Hello

As a requirement, we are creating generic extractor on COOI table with delta mechanism.

there is a timestamp field avaialble at the base table.

Timestamp is having value like : 7.787.478.140.000

This field gets changed whenever the purchase order gets changed.

So, delta is enabled on this field with Safety interval; Upperlimit as blank and lower limit as 1800.

But after transporting the datasource and for testing if I chnage any purchase order via ME22 transaction it gets chnaged in the COOI table along with timestamp but that record is not getting captured in RSA7.

I tried reversing, the safety intervals, but still no luck.

Can anyone help me with this?