[cpx86]

Oh that one - yeah I've always steered clear of DataContractJsonSerializer. Never understood why they did it so weird.

To be fair, RFC 3339 wasn't even published back when this class was implemented (in .NET 3.5) so I guess they just went with whatever worked for their needs. ¯\_(ツ)_/¯

[da_chicken]

I'd be quicker to believe that it's because 2007 was still in the middle of Steve Ballmer's Microsoft, where embrace-extend-extinguish was their de jure practice.