Wireshark sample keylog decrypt not working

While trying to track down why my key log files are not working I found the sample captures on the WIKI. The "dump.pcapng" with associated "premaster.txt" does not seem to be working for me.

1. I have no RSA keys in my RSA keys list
2. Pre-Master-Shared log filename is set to the "premaster.txt" I downloaded from the WIKI
3. SSL debug file is set to a valid file/path

Contents of resulting SSL debug file:

Wireshark SSL debug log
Wireshark version: 2.2.6 (v2.2.6-0-g32dac6a)
GnuTLS version:    3.2.15
Libgcrypt version: 1.6.2

I must be doing something wrong?