Decision Mining in interface quietly fails when reading variable names

[AdamBanham]

Decision mining within ExogenousInvestigationTask can quietly fail and lock out further attempts for mining. Probably should handle failing in a more graceful manner. Likely an issue with having special characters in variable names.

[ExoDiscoveryInvestigation] Found class types : {exogenous:#fines:POS:transform:slope=CONTINUOS, amount=CONTINUOS, expense=CONTINUOS, exogenous:$fines:POS:transform:slope=CONTINUOS}
[ExogenousInvestigationTask] Generated the conditions for decision point sink 8 with f-score 0.0
[ExogenousInvestigationTask] Generated the conditions for decision point source 11 with f-score 0.0
[ExogenousInvestigationTask] Error occured in work : URLDecoder: Illegal hex characters in escape (%) pattern - For input string: "fi"
java.lang.IllegalArgumentException: URLDecoder: Illegal hex characters in escape (%) pattern - For input string: "fi"
        at java.net.URLDecoder.decode(Unknown Source)
        at org.processmining.datadiscovery.plugins.DecisionMining.wekaUnescape(DecisionMining.java:1037)
        at org.processmining.qut.exogenousdata.data.storage.workers.InvestigationTask.doInBackground(InvestigationTask.java:853)
        at org.processmining.qut.exogenousdata.data.storage.workers.InvestigationTask.doInBackground(InvestigationTask.java:81)
        at javax.swing.SwingWorker$1.call(Unknown Source)
        at java.util.concurrent.FutureTask.run(Unknown Source)
        at javax.swing.SwingWorker.run(Unknown Source)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
        at java.lang.Thread.run(Unknown Source)

Crash interface looks like the mining is completed but locks out next steps and buttons are not re-enabled.