Yes, you're correct it does fail. Although just changing the browser language in FF on Linux will also make it fail.
The debug info is in the attachment.
This is a known bug in date parsing. Works fine in an en locale but breaks in most other. It's fixed in the next release.
Looking for new beta users -> Co-Founder of Acompli. Previously worked at Zimbra (and Yahoo! & VMware) since 2005.
If you want to patch your release, change the following line in both AjxText.js and Ajax_all.js from:
var value = parseInt(s.substring(head, tail));
var value = parseInt(s.substring(head, tail), 10);