Yeah happens with Robots too.
I suspect some sequence of events is confusing the code that usually buffs your henchmen with both "upgrade" powers when you move to a new zone.
It's actually become rather annoying, since on at least one of my Masterminds I prefer to run with my Assault Bot only having the level 2 upgrade but not the level 1 one (for more burn missiles!), so when it happens I need to dismiss and resummon my Assault Bot and re-buff it...
Yea this happens with Mercs as well.
Captain Den'Rath 53* Merk/Traps MM, Rivona 50Energy Blast/Time Cor,Victoria Von Heilwig 53* Dual Pistols/Traps Cor, Crab Spider Webguard 53* SOA, Accela 53* Bot/FF MM,Valkyrie's Executor 53* Broadsword/Shield Def Scrap. On FREEDOM! @Knight Of Bronze
"Hypocrisy, the human inherent." "Let not this work be wasted, apply yourself always."
i think this bug happens with all mm primaries, and its even done it to me when using seeker drones on occasion
With Robot Traps at least, I noticed that I need at least one pet upgrade for this to work.
So I summon the 2nd pet upgrade which is a lower endurance cost then the first and then I summon FF Gen which is only 16 endurance instead of 32 endurance. I get the 1st buff on all the pets for half the price or a free FF gen, depending on how you look at it.
To me, right now it makes up for the darn pets getting frozen when you zone.. I have been dismissing pets before zoning but not into missions assuming I stayed in the same zone. Sadly today I had the pets freezing when I zoned into missions even when I never left the zone with them.. 
1. Why Soft Cap is Important : http://dechskaison.blogspot.com/2011...important.html
2. Limits: http://paragonwiki.com/wiki/Limits
3. Attack Mechanics: http://wiki.cohtitan.com/wiki/Attack_Mechanics
4. Rule of Five: http://wiki.cohtitan.com/wiki/Rule_o...e_Law_of_Fives
I wouldn't get too attached to the bug though. It'll get fixed. At least they fixed the bug where henchmen would forget they work for you upon zoning.
"The danger is not that a particular class is unfit to govern. Every class is unfit to govern." Lord Acton
Madam Enigma's History
I'm a DS/trap mm and I have a neat trick/bug/glitch/awesome technique.
Sometimes when I resummon my ff generator before it explodes on its own, my character automatically rebuffs my henchmen with Enchant Demon and Abyssal Empowerment at no end cost. This usually works best when I buff all my guys outside an instance and summon the ff on the inside.
Has anyone else experienced something like this?