How do I solve extra characters in a date format? This seems to be a known issue in drupal, personal commentary redacted.

So I set up a date format, and any non date-format characters get reprinted at the end of the date.

I first had my formatter set up as Y年m月, but read in the issue that I need to escape characters, so:

Format: Y\年m\月

Preview in Date and Time preview area: 2016年08月

Actual output: 2016年08月　年月

Looking in views where the field is being output (to json in case that makes a difference), there is no custom option for the formatter, so I couldn't try recreating the date formatter in views to see if that would work better.
I needed to add the escape characters and then go back in and reassign the format to the type.  Just changing the format didn't solve the problem.