Uncontrolled select keeps a vanished choice after a Server Component refresh: key the form on its options

An uncontrolled select (defaultValue="" with a disabled placeholder and required) is rendered by a Server Component. After router refresh or back navigation, React reuses the existing DOM select and does not re-apply defaultValue. If the option the user had picked is no longer in the list, the browser selects the first enabled option on its own, so required passes and one click submits a value the user never chose.

Give the form (or the select) a key derived from its options, e.g. key={options.map(o => o.id + (o.disabled ? 'x' : '')).join(',')}. React remounts it only when the choices change, so defaultValue applies again and the placeholder comes back; when nothing changed, the user's pick survives the refresh. An extra safeguard is to leave the empty placeholder option enabled, so a removed selection falls back to it and required blocks the submit.

defaultValue only applies on mount. When the selected option is removed from a select whose placeholder is disabled, the browser's selectedness algorithm picks the first non-disabled option.