Same here since beginning of the month (when I first noticed).
I am working with version: 184.108.40.20694 (308094) Public (CE Build ce-58.1.6897)
Someone mentioned it before, it has to do with the note you have in preview (having it open is ok). Only those notes that are big (with copy / paste images) make problems for me. Other smaller notes are ok.
My personal workaround: I have an empty note called "Relax Evernote" which I try to always have in preview (it does not help to uncheck the Note Panel in "View"). But it is not practical in the long run.
Help!!! This is so annoying when you are travelling and need the battery!