BBM on iOS doesn't convert %20 to space when I share via an <A> tag

Question

I am trying to share a message (text only, not an invite) via an <a> tag from a website to the BBM app.

Here is my code below

<?php  $encodedBBMmessage = 'The%20Message'; ?>

<a href="bbmi://api/share?message=Share&userCustomMessage=<?php echo $encodedBBMmessage;?>">Send via BBM</a>

It shares successfully on Android but on my BBM app (version 300) on iOS 10.1.1, it doesn't change the %20 to [SPACE] after populating the text box.

Even when I don't encode the userCustomMessage, the problem persists.

Can anyone help me understand why this is?