This does not work:
When doing PIE the editor log also shows that material parameter named ‘None’ was trying to be set.
As a workaround, this works:
So the problem is entirely in the static parameter name binding in blueprint, as you can see, they work when coming from a local variable.
UE4 4.5.1 github commit 4438f90924af292b11b58b6dd4ba02f0af9af749 on 4.5 branch (2014/10/17)