• In Chrome happens infinite loop in month Oct/2015 (see attachments).

• In Firefox happens duplicate days in 2015/Oct/17 (see attachments).

I believe that's problems are happening because is 'Daylight saving time'. When add a schedule in Firefox on Oct/17 for example, happens other problems.

My timezone is (UTC-03:00) Brasília.

OBS: I debug a bit and I think I found the likely problem of infinite loop. Look attachment 'line-problem.png'.
Javascript: CalendarsMonth.js
Method: _resetDayPosition