[Client][5v5 Rank] [Champion Selection] Lock In Button Greyed out after I chose a summoner's spell.

This happened to me right now on champion selection:

I went first in line, so I banned three times. After that, I was first pick, instantly after the last ban. I picked Leona. I changed my second summoner spell from Teleport to Exhaust. After I changed that spell, the Lock In button greyed out.

While I did picked that champion, I had to wait 20 seconds for it to auto-lock.

To recreate this effect, just second pick the second spell.