I create a checkbox field like this

this field is used to store boolean value if a lead needs to be sent a Whatsapp template or not. I create a deluge function to make it selected or not.

if a lead is created by Whatsapp (Business Messaging) at 6:00 PM or above then the deluge function will change that checbox to selected,  I put the function on Workflow rules like this

The checkbox is edited without issue. that workflow rules works as expected.

when the checkbox is edited by that function via workflow rules, then I want to send whatsapp notification via worflow rules like this

unfortunately the whatsapp message will never be sent automcatically

but when I edit the checkbox manually (not by function) to be selected like this

then it will sent the whatsapp message

what went wrong in here?