Sitecore custom rule based configuration patching not working with word beta

I faced a weird issue while doing a custom rule-based patching in the Sitecore. I defined a setting like the following:

<add key="beta:define" value="enabled" />

and then create a patch as:

<?xml version="1.0" encoding="utf-8" ?><configuration xmlns:patch="http://www.sitecore.net/xmlconfig/" xmlns:role="http://www.sitecore.net/xmlconfig/role/" xmlns:beta="http://www.sitecore.net/xmlconfig/beta/"><sitecore role:require="Standalone or ContentManagement or ContentDelivery" beta:require="!disabled">

but this did not work.

The strange thing is that when I replaced the word beta with any other word it worked fine, e.g., when I used the following:

<add key="prd2:define" value="enabled" />

and

<?xml version="1.0" encoding="utf-8" ?><configuration xmlns:patch="http://www.sitecore.net/xmlconfig/" xmlns:role="http://www.sitecore.net/xmlconfig/role/" xmlns:prd2="http://www.sitecore.net/xmlconfig/prd2/"><sitecore role:require="Standalone or ContentManagement or ContentDelivery" prd2:require="!disabled">

then it works fine.

Any idea?

FYI: I am using Sitecore 10.3.2 with sxa.