|Ellipsis 2.0.2, WoW 4.0.3 live, Fire spec Mage. Added the following glyph to an open slot: Glyph of Dragon's Breath. Error was thrown up by Ellipsis as soon as it was inscribed:
["message"] = "Ellipsis-2.0.2\\Core.lua:398: attempt to index field '?' (a nil value)\nCallbackHandler-1.0-6:147: in function <...onLoader\\CallbackHandler-1.0\\CallbackHandler-1.0.lua:147>\n<string>:\"safecall Dispatcher\":4: in function <[string \"safecall Dispatcher\"]:4>\n<in C code>: ?\n<string>:\"safecall Dispatcher\":13: in function `?'\nCallbackHandler-1.0-6:92: in function `Fire'\nAceEvent-3.0-3 (Ace3):120: in function `OnEvent'\nStopAddonMessage-1.6.1beta\\core.lua:282: in function <Interface\\AddOns\\StopAddonMessage\\core.lua:211>\n(tail call): ?:\n\n ---",
["type"] = "error",
["session"] = 583,
["counter"] = 1,
}, -- 
EDIT: haven't been playing/testing much in the past week. Upgraded from v2.0.0 to v2.0.2. Doing a file diff with v2.0.1, looks like the code issue started there. The section of core.lua from lines 393-399 is not working properly: Special once-only check for mage talents on water elemental.
Another option besides custom code for talent detection: LibTalentQuery-1.0.