confirmed on the following versions:
3.6.3 (Windows 10)
3.7.0 (Debian 9 & Windows 10)
3.7.1 (Debian 9)
a dictionary created with the dict() function will not always return the appropriate dictionary object. The following code produces the bug on all stated versions except 3.6.3/Win10, which exhibits slightly different behavior.

a = ['1','2','3']
b = [1,2,3]
c = zip(a,b)
print(dict(list(c))) #gives empty dict
print(dict(list(zip(a,b)))) #gives {'1':1,'2':2,'3':3}
d = zip(b,a)
print(dict(list(d))) #gives {1:'1',':'2',3:'3'}