Ok this one needs a bit more explanation.
I found this ring and I use it now that switches Max Health and Max Focus.
I am near the end of the crucible run and was buying the random echoes and suddenly my Health drops to 0? I don´t know because I can not look at it. I also can´t open the echoes view to see what echo may have caused this. Basically I can move the mouse and thats it. I can´t even open the main menu. I think there was an Echo that is like: You have no Foucs. That may be the culprit.
This should be handled somehow I would have been less irritated if I had died because of 0 Health ;), if it actually is 0.
I had to use alt+f4 to leave the game 
Files: Player.log and Player-prev.log, DataStore folder, …
Files
EDIT: Video
The Ring is called: Scarlet Ring
The Echo is called: Fleet Assault
If there are other Echoes that have a similar line like “Focus is removed” that will probably cause this too.
FYI: I tried to post this in Bug reports but the Forum? Does not seem to recognize the uploaded files in gdrive and won´t let me post the bug… I spent a lot of time with this and didn´t get this to work whats wrong there?