Elise spider on bench (not sell-able)

An Elise spiderling took up a spot on my bench, and I couldn't sell it. I don't know if this is known yet, so I thought I'd report it.

The setup:

1. It's the end of a PvP round, we're waiting for other fights to end
2. My Elise had spiders out and was still alive at the end of the round
3. I sell a unit that's on my bench
4. The spider takes the spot of the sold unit
5. I try to sell the spider with E, but it remains on my bench and instead it seemingly drops from Tier 1 to Tier 0 (still before other fights had concluded)

The effects:

• I can't sell it
• It has a red health bar
• It takes up a slot on my bench
• When I put it in the field instead of another champion, it disappears at the start of the next fight, and the left-most champion gets put on the field automatically. And when the round is over, it reappears on the bench to take a spot.

Please let me know if any additional info is needed.