I was thinking over watered from rain, but if rootbound, they could be under watered, as both ways perty much has same effects.
I hope pots have drain holes.
Pull them out. Like, now.
See if roots are healthy.
If there rootbound. Put them, less pot, into a bucket full of water for a good half hour, them rub rootball to loosen up some outside roots so they can grow out of rootball.
Then treat with peroxide water and up-pot them as @ScotTi
For new soil, I'd use equal parts of perlite to soil you have. Barley moistened, then wait a week to water.
If roots are rotten, remove all rotten roots. Do peroxide thing. Put some cinnamon on cut root ends. Then repot, with fresh soil as I directed above.
Best, to you, and them.