agents always keep busy, cannot be stopped by stop button at agent management page

[jackychen]

hi, after I run testing for some minutes, I found some agents always keep busy status, so there will be not enough agents avaliable and my perf test cannot be started.

I go to agent management panel, found some agents' status is always busy( no other people are using them), so I attempted to stop the busy agents by stop button, but no use. They still are busy status.

can anybody know what happened on this?
is this a bug of ngrinder?