Not sure if this has already been addressed (don't see it on forums) but this glyph seems to randomly stop working sometimes. When I attempt to cast lightning bolt on the move with the glyph equipped it just says 'Can't do that while moving'.
This has been happening to me on occasion too lately, although a relog clears the error. Not sure what causes it, though I've most often noticed it while flying around Northrend doing Argent Tournament dailies. I get off jousting and go kill some cultists, Lighting Bolt doesn't work on the move. I relog, it works. Finished Icecrown dailies, did the sword quest in Dragonblight, Jormungar quest in Storm Peaks, and just flew up to Hrothgar's Landing to find that Glyph of Unleashed Lightning stopped working yet again.
the cast movement effect of the glyph seems to disable upon enterring a crossrealm zone or being phased to another realm and returning etc, you can unlearn and relearn to activate the glyph otherwise in my experience.