Getting warnings for OverlayTrigger in Reactjs

Warning for Overlay Trigger

I have used OverlayTrigger component of react-bootstrap, it gives warning as shown in the image above.

Code:

<OverlayTrigger delay={{ show: 250, hide: 400 }} overlay={"hello"} l="true">
   {children}
 </OverlayTrigger>

or

const value = "true";
<OverlayTrigger delay={{ show: 250, hide: 400 }} overlay={"hello"} l={value.toString()}>
   {children}
 </OverlayTrigger>

Tried using attribute l={"true"} or l={value.toString()}, yet not worked.

Expected the warning to be removed but it still existed in the browser. Can anyone help remove this warning?