The reason for the issue is the fact that JAMB has not sent your details to the new schools you changed to.
However, JAMB has disclosed that soon enough, details of the affected candidates will be sent to their various schools and afterwards such candidates will be able to register for the POST UTME screening of their various schools.
JAMB will soon send their details to their various schools which will enable them register during online registration on their various school portal.
According to JAMB, all Institutions have been directed to ensure that all candidates are considered for their various PUTME
Candidates should not panic as they would certainly sit for the PUTME in the Institutions they have made changes to.