export to Excel mangles dates #21

I have a report generated from MySQL that shows date and time correctly in the web UI. Underlying column is a MySQL DATETIME. When I export the report to Excel (Office 2016 for OS X), the date is mangled. In the web UI, it is "2018-06-29T23:22:59.173", but in excel it shows "1/6/1900 12:00:00 AM". Other dates are similarly mangled.

This happens with the latest published docker image.