British man Aidan James, who fought against ISIS militants, convicted of attending a terrorism training camp. He was in an Iraqi camp where the banned PKK group was active. First conviction of its kind in the UK.
James attended a camp in Iraq where the banned PKK group was active (it's a Marxist Kurdish group that has long been banned under terrorism legislation). But he ultimately fought with the YPG - Kurdish units in Syria, which are not banned under terror laws. 
In other words, what the judge described as Aidan James' "quite fleeting" time with the banned PKK Kurdish gr,oup led to his trial. His actual fighting against, as a volunteer with the YPG was not the crime.
