I used a b2c starter pack to create my MFA B2C sign in policy with phone number as a factor. But for some reason it doesn't work as expected. First time when I sign in it work fine - the policy is asking me to verify my sign in via SMS and then I got a token. But when I run the flow immediately after my 1st sign in, it shows the same phone verification page while it shouldn't. I expect that it should silently sign me in without phone verification. So looks like MFA session is invalid. How to fix that?