add linear gradient to a border react native code example

Example: react native linear gradient border radius

You might fixed it by wrapping the LinearGradient on a View component and applying the borderRadius to it instead of directly applying it to the LinearGradient.

<View style={styles.imageContainerIOS}>
    <LinearGradient ... />
</View>

const imageContainerIOS: {
    borderBottomLeftRadius: 5,
    borderBottomRightRadius: 0,
    borderTopLeftRadius: 5,
    borderTopRightRadius: 0,
    overflow: 'hidden',
},

...
Except this, you can try to add overflow: 'hidden' to your style object. It may be fixed your problem directly.