This bug applies to the conjure spells for Flame Axe, Frost Bow and Lightning Hammer.
If the Elementalist begins to cast the conjure spell and then: dodges, cancels (escape key or sheathe weapon key, etc), or is interrupted by regular means (presumably), the conjure spell will then go on cooldown for 1 minute, and no conjured weapon will appear, in either the caster’s hands or on the ground. Again, this only seems to apply to Flame axe, frost bow, and lightning hammer. Earth shield and Fiery greatsword seem to function properly.