Hi, I know this topic is aged a little bit but Im seeing the same problem as the OP stated. I have the same issue but it seems to go farther than just HUE retaining it’s color when it’s turned back on.
I setup a “Bedroom Movie” routine. During that routine, it hits a switch called “MB Movie Lighting” which triggers the smart app Smart Lighting . The Smart Lighting app turns on the master bedroom switch, then turns the lights blue and sets them to 20%.
Now, every time I turn on my master bedroom lights via smartthings (not when I use the physical switch), they start at the standard “white” that hue does when you initially turn them on, but in about 5 seconds, the lights turn blue again.
I changed the Smart Lighting app to do away with blue and just use the “relax” color in an attempt to fix the issue. This was the ONLY place where the master bedroom lights were changed any color at all.
But the blue lives on. I setup “Smart Wakeup” this morning. Routine hits the switch to turn on the lights first. They start at 100% dim (for about a 1/2 second) then go down to 10% dim. For about 1/2 second they’re white then the magically turn blue. Reminder, I have no automation that turn the lights blue anymore.
While the Smart Wakeup app is running, I go into those hue bulbs directly in smartthings and hit “reset color”. They turn standard color (no change to the dim % occurs) but after about a second they turn back to blue!!
So at this point, unless I use the physical wall switch (Leviton Zwave swich) BY HAND, I have blue lights in the master bedroom.
Someone earlier in this thread mentioned that this was a HUE issue because they go back to thE color they were before they were turned off. Not trying to be a jerk but, that’s simply not true. To prove it, change your HUE to red. Then turn them off at the switch, and back on again. The color will be reset to standard. I know this very well because my wife uses this off,on method to reset light colors instead of using ST.
Any other thoughts on this issue? Would love to get this solved as the master bedroom calls for more than blue lights. 
Nick