Unstable Glyphbridge casting bug

Unstable Glyphbridge won't cast if there isn't a target for it's first ability. This must be a bug as it's a support not a spell, and it has further in-play abilities with the Crafting mechanic.
https://www.youtube.com/watch?v=3wyefkCQJQI

NB - this is different to the bug reported by Killroy in January this year, which is now fixed.