Xiaomi
Turn Auto-capitalization On or Off auf Xiaomi
Auto-capitalization on Xiaomi phones watches for sentence breaks and automatically capitalizes the next letter you type. This runs through the built-in keyboard's text correction engine inside MIUI's input settings. It speeds up normal messaging, but causes problems when you paste usernames, email addresses, or code where the first letter has to stay lowercase.
Where to find the setting
Open Settings ➔ Additional settings ➔ Languages & input ➔ Manage keyboards ➔ Settings ➔ Text correction. Toggle Auto-capitalization off to stop it, or back on to re-enable it.
Turning it off removes automatic capitalization everywhere in that keyboard, including chat apps and browsers, since the setting is global to the keyboard rather than per app. If only one field needs different behavior, switching to another installed keyboard is the only workaround, since MIUI does not offer per-field exceptions. Side effect of disabling it: you need to capitalize sentence starts manually, which slows down casual typing.