The overflows are gone in beta 1211.
Just an observation that, while the new API expanded the range for $asctime(N) from the 2nd second of 1601 thru the last second of 9999, the range for $ctime(date-string) remains the same. For me, valid limits are:
//!timeapi on | var -s %hi_valid $ctime(Jan 01 01:59:59 3001) , %low_valid $ctime(Jan 01 00:00:00 1970)
//!timeapi on | var -s %hi_invalid $ctime(Jan 01 02:00:00 3001) , %low_invalid $ctime(Dec 31 23:59:59 1969)
I'm guessing the higest valid ctime(date) conversion depends on your offset from USA Pacific.