Ay 18-19 return of income transferred to ao

I got a message on 21st March that my return of income has been transferred to jurisdictional AO with reason - "Processing of your return has already been initiated by the Jurisdictional Assessing Officer (AO)". I had claimed Relief 90 in my ITR for foreign tax credit. Is that the reason for the manual assessment? Do all relief 90 ITRs go to AO or if there is some discrepancy in the numbers?

What can i now expect a message from the AO? What are the general timelines?

Also can i amend/revise my ITR after it has been transferred to AO or i should not do that?