Arelith

When you cast Fire Imbue on your weapon as spell sword afterward cast blades of flame onto the same weapon it overrides the fire imbue and when the duration of the spell ends for Blades of Flame it clears the elemental fire damage from the imbue but keeps the enchantment bonus as shown in the screenshots.

Looking at the code, this appears to have been fixed. Please reopen the thread if results differ.