There isn't enough information to debug here. It's possible that this warning doesn't come from lottie as well. If you could add more repro steps, please reopen.
I got the same error when I left out the style attribute with a width and height on the Lottie component:
This works:
<Lottie
style={{
width: 50,
height: 50
}}
loop
source={LottieAnimation}
ref={ref => { this.animation = ref }}
/>
This doesn't:
<Lottie
loop
source={LottieAnimation}
ref={ref => { this.animation = ref }}
/>

This seems to be related to specific assets. Is also happening to us.
Most helpful comment
I got the same error when I left out the style attribute with a width and height on the Lottie component:
This works:
This doesn't: