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[14:51:21 CDT(-0500)] <cindyli> thanks, Bosmon.
[14:52:55 CDT(-0500)] <Bosmon> In the end it was caused by the implementation of the new framework fluid.isPlainObject utility
[14:53:04 CDT(-0500)] <Bosmon> Which gives different results on IE8 to other browsers
[14:53:26 CDT(-0500)] <Bosmon> In particular, Object.prototype.toString.call(null) amazingly produces "[object Object]"