Hi.
Actually in older versions i had conflicts with this as well (1.8.7+)
After i had issues with it i made sure not to use same names for globals is it might have been fixed somewhere in between version tho.
I do think that when creating a local value it should check globals and give a already exist warning as its not a good practice to use the same names for global and local
(in c# scripting this can also give errors.)