Suricata

Scenario: I want to manipulate a flow variable that I've extracted with a PCRE with a Lua script. Whenever I call the SCFlowvarGet method in the Lua script it returns "null" and not the value of the flow variable as it should.

Attached you can find the files that I am using (PCAP, rules, lua).
I'm using the following Suricata call:
suricata -v -r /home/suricata/test.pcap -S /etc/suricata/rules/test.rules -k none

As you can see out of the resulting eve.json file (attached) the rule works and also the variable is extracted. Furthermore the lua script is triggered and executed as the print commands of the lua script are in the console output. Also you can see in the console output that the "testVar" is not set (in my opinion it should be set there). It this a bug or am I doing something wrong in the script?