Unable to edit components after previously changing all users' user logins from the format <firstname>.<lastname> to their email address

When we first registered users in our JIRA Cloud instance, we registered everyone in the format <firstname>.<lastname>. As our user base grew, we decided to change everyones' user login to their email address, as we could guarantee that it was unique.

This has already caused a problem in JIRA Portfolio (see JPO-1381). I believe that it has also caused an issue with the Components functionality of JIRA, which is described below.

Steps to reproduce on our Cloud instance:

1. Navigate to Components section of a Project (see )
2. Click on Actions > Edit against any of the listed components
3. Dialog box is displayed (see ) - note that the Component Lead is listed as raj.mehta (which is the way we previously had users registered in our instance)
4. I tried to change myself to Component Lead. JIRA correctly found me in the instance ( ) and when I clicked save the following error occurred "The user gary.bates@phe.gov.uk does not exist" (see screenshot )

However, I definitely exist in the instance with that email address! And you can see that JIRA has found my profile picture against my name too.

I believe this is highly likely to be a similar issue to JPO-1381 (the fact we have changed our user logins across our instance from <firstname>.<lastname> to email address).