Missing System Generated Behavior after condition was set

[ZoroK]

Hi all, i need some helps here.

I am giving condition (Yes/No) to a system generated behavior "Add" to add a reference row to other table.

now()<[Invoice No.].[Created Date Time]+"001:00:00"

but the "Add" button is missing even the condition is true.

I tried giving other condition like useremail(), it works perfectly, the button show up as it should. Any advise on solving this? or is it a bug? Thank you.