This afternoon I was all by my lonesome, datamining.  Sure enough, a slew of Data Sentries appeared and took me under fire.  One interlocked me.  I fought on autopilot, and took a quick call.  When I came back, all the datasentries were dead, the last one being killed by a Level-100 Agent!

Apparently, someone else's Level-100 Agent (there was another team datamining near me) had gone off-mission to come over and help!  It's at times like this that I love being a machinist...

And then I got the data-cluster opened, too! 

Heh...  I was in stealth, stalking Void the other day when an Agent popped up to get me.  Since I was in stealth, the agent chose the next available target:  Void.  It was great fun.

I doubt it has anything to do with being a Machinist.  If the target of the Agent is not readily visible, it will move to the next available target.  The Agents do flag hostile for Machinists as well, so you were probably lucky it didn't start blasting at you!