In my recent testing on superSU app and binary. I was able to test versions of SuperSU and found out that:
1. from version 1.51 till latest (2.04 beta). SuperSU binary has an issue on detecting sd card mounting (internal and external) on our device. This caused Titatium backup and other root apps that access sd cards to fail.
2. Using SuperSU version 1.42 to 1.45 do not have the issue above. SuperSU app and binary was fully working.
I also reported this to SuperSU thread of Chainfire. Here
Hope this gets resolved soon.
Note: The official SuperSU version 1.45. You can flash this to resolve Titanium backup not working issue. REMEMBER to not let play store update the superSU app to the latest version until the issue is resolved by Chainfire.