When I use webix.Date.strToDate("%c") to parse my ISO8601 dates, it fails on dates that have time zones in them unless I use webix.env.strict = true;
Here are some sample dates for you to test against:
// can read this in any case:
“2016-05-31T11:41:55.604864”
// can NOT read this without strict:
“2016-05-29T18:31:00-07:00”