Not sure if this is a bug or not, but anyway…
If I try to apply one PP material twice to volume or camera, the last blendable will be the only one wich will work.
Here is my example material. As you might guess, two blendables will make the screen to be fully black.
http://s1.uploadpics.ru/images/-yLf3JTwKb.png
But if I apply this material as two blendables, this will happen:
http://s1.uploadpics.ru/images/Z1YFJlavKZ.png
Only one applies…
Same thing If I apply them as two dynamic instances through BP.
http://s1.uploadpics.ru/images/WJyhug6PYW.png
But if I apply two different materials, everything works as expected.
http://s1.uploadpics.ru/images/ZyCkyZTwK-.png
http://s1.uploadpics.ru/images/ZkNZy-TDtZ.png
So… I’m not sure this should work like this, so reported as a bug.
For my work it is not suitable to make many materials to apply same effect more than once (those effects will be applyed in different screen locations, so I need to apply same material with different parameters), as they should apply dynamically.