Having the same issue. I have also done some testing to try finding a workaound for the issue.
It seems from my finding that the problems are related to the account you are trying to transfer to.
I tested withdrawing the Account Holder Transfer request for Useraccount "a" and then make a new one to Useraccunt "b" for testing.
For useraccount "b" I was able to get the "Review Agreement" option instead of "Reject" and "Learn More".
I then tried to remove the account I was having issues with (Useraccount "a") from Users in the Developer account, re-invite the user and then again make a new Account Holder Transfer request. The problem prevailed, and this did not solve the issue.
Based on this it seems to be related to some state or data related to the useraccount that prevents it from working as it should. I don't know what differences between the accounts could cause this problem. Both accounts had the same role and permission on the Developer Account User's list.