assignment failure of the same permission set in identity center

Hi I created an organization with two accounts and a single user in the identity center for sso access
Then I created a single permission set with customized statements in an inline policy.
In iam identity center dashboard I'm trying to assign the same permission set to both the accounts in my organization: but when I assign to the second account the same sso user (in the step1) and the same permission set in the second step I got

0 of 1 assignments configured successfully. Your users can access the AWS Account with the permissions you assigned. 1 of 1 failed to be configured. You can retry submitting them, or you can leave the page and the failed assignments won’t be submitted.

Is this scenario expected? In the manual I read

You can create a single permission set and assign it to multiple AWS accounts within your organization. You can also assign multiple permission sets to the same user.

Is a provisioning issue? Do I need to wait for the permission propagation? Should I erase the second account and retry? If I try to login in the sso access portal I can only see the first account of my organization.. Should I create a different permission set with the same rules? but why?