Layout load before event isn’t triggered

I have an event

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:Event/etc/events.xsd">
    <event name="layout_load_before">
        <observer name="redirect_pro_homepage" instance="CpyCheckUrlObserverRedirectVisitor" />
    </event>
</config>

In local env; this observer is called.

In my sandbox env this observer is called.

In my preproduction env, this observer is not called.Can’t understand why.

Any explanation on what might cause this ?