Transference and Grey Heath bar

[Krisevol]

When I try to use transference to leave my warframe, I can only come out for a second and it puts me back in.  It doesn't always do this, as I can do kuva missions and still use the dash moves, but sometimes I can't use it at all.

Also does anyone know what it means when the health bar turns grey?

I made a quick video showing that I can't leave the frame, and the heath bar.  

 

 

 

[Voluundr]

You can't go into Operator mode when at Extraction, as for the grey health bars, I can't answer that one.

[elitetrollz]

The grey bar in your health means that you are invulnerable to damages.

 

Try to Tap 5 or whatever your key is binded to use "Transference" and not holding it.

[AXCrusnik]

Can't use Transference at the Extraction.

And

Health Bar Changes
When an enemy or ally becomes invulnerable, their Health bar will now turn grey and an icon will appear over their Health bar denoting invulnerability. 

As an example, take a look at how the Jackal looks now when he's invulnerable:
https://pbs.twimg.com/media/C23_RC4WIAAYL3F.jpg:large