Hello,
This little sample is working with the "www.plantuml.com" version (.2017.19beta12), but not with last beta (1.2017.19beta17):
@startuml
start
repeat
' :Test something;
if (Something went wrong?) then (no)
:OK;
' comment break and there is no more problem
break
endif
repeat while (Something went wrong with long text?) is (yes)
stop
@enduml
http://www.plantuml.com/plantuml/png/ROun3i8m34LdSeg_jRq27JW00mDS8AKkYThObMCfS7lIgcnuUhBUjtysh-QKLlBc6k3ye6p8aiX2v5VlK2TEQE-_5GgneQZmwzB10Z5QbcuNQ_vsxTq9QF2Kb3PpK3_3yxYfIeWPB4XISLKP5af7Sb3oyyx4OvoEJYWXBlJ_FKgqW6KZexVLDlLu-w7SkMooVW40