Source Tag Path Binding is not being Enabled

I Have a UDT of References Tag for these Tags I am binding the Source Tag Path with UDT parameters, the problem I am facing is all these tags have same bindings, so I am selecting all the tags and pasting the Source Tag Path Binding but these bindings are not being enabled But when I give an space after the path it is getting enabled Not sure What is happing or I am doing something wrong can anybody help me with this
Binding without giving space

Binding when space is given