Already existing user in the database, when trying to login again using OICD gets a 1 added after his username

[pablodamico]

A user who has been using the synapse matrix instance for some time, started facing an issue when logging in using OICD, that adds a 1 after his username.

Example:
The user is @jsmith:my.synapse.instance and he has been using this account for months.

Now, when logs in, he gets prompted to create securty keys, passphrase etc, and the user ends up being a different user:
@JSmith1:my.synapse.instance

THis is the only user facing this issue in the whole instance. Both users jsmith and jsmith1 are now in the database as different users.

Thanks!