UpdateUserAsync not properly saving data in Hosted Service

[pippinmole]

Describe the bug
When setting the username of a user, updating it (through userManager.UpdateUserAsync(user)), the user data is not stored. This is clearly shown in the screenshot where I get the user straight after, to which the names do not match, but sometimes they do?

It is worth noting I am using Cronos, a cron-style scheduling package that allows me to run background tasks every period of time.

To Reproduce
Steps to reproduce the behavior:

1. Register a Cronos job inheriting from the CronJobService
2. Inside DoWork, await a delay and try and update the user
3. Observe the property you update not reliably being updated

Expected behavior
User gets updated every time the method is called and awaited

Screenshots

Environment (please complete the following information):

• .NET 6
• AspNetCore.Identity.Mongo v8.3.3
  

Additional context
Add any other context about the problem here.

[pippinmole]

It may be worth noting that if I change the IAppUserManager (my interface) to UserManager (MongoDB .NET library), it still produces this error, as shown in the images below