Your timestamp serialization/deserialization fucntions mention that they convert "ISO" timestamps, but they only provide partial coverage of the ISO-8601 standard. The 1.1.7.33 release addresses a little more of the spec, but it still isn't enough for my use case (JIRA API) where a date but not a time is provided:
2016-12-22
According to the wikipedia page, this should be valid ISO-8601 https://en.wikipedia.org/wiki/ISO_8601
Optimally, you should use an off the shelf ISO-8601 converter that supports more of the spec, but it doesn't appear that one exists (maybe a good candidate for an OpenG function?).