Mail password overwritten by Account manager password, even if they are different accounts

• /e/OS version: 2.9-t-20250321478215-official-FP5
• Device model(s): FP5
• Impacted Application: /e/OS Mail /e/OS Account Manager

The problem

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Steps to reproduce

• have an e-mail address from any mail provider (other than Murena cloud), and configure it in Mail app (in my case, an e-mail hosted by Infomaniak)
• in Account Manager, configure a nextcloud account (other than Murena cloud) to synchronize your calendar, notes, photos etc. Using the same e-mail address as you configured in your Mail app (not 100% sure it's necessary). But make sure your nextcloud account is not hosted by the same provider as your e-mail provider (i.e you used a different password for Mail and Account Manager). In my case, it's a self-hosted nextcloud instance
• with /e/OS 2.8 and below: everything works fine
• upgrade to /e/OS 2.9: your Mail account password is overwritten by the Nextcloud password, and is refused by the e-mail provider (because it is indeed a wrong password)

If you put back the right password in your Mail account, it temporarily works (new mails are fetched), but the password is overwritten again in the following minutes. So the problem comes back very quickly.

In short: e-mail becomes unusable since v2.9, in that case.

I'm afraid this will affect a lot of people not using Murena cloud

Technical details

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