Are you in Alaska or Hawaii or Florida. Do they get any Sunlight and so on?

Thanks for the comment and question! I am in OH and yes, they get about 4-5 hours or so of direct or semidirect sunlight. The worst offenders have been moved to the side out of the light for now, because I wondered if they might have been getting sun burned.

Looks like the most exposed leaves are the ones browning, so I would say too much sun. You can't fix the already damaged leaves, but the new leaves will be okay if you get them out of direct sun going forward. It looks like they may need some fresh bark mix, too. If the bark they are in is broken down, they could be getting too water-logged, which would rot the roots and cause limp leaves.

Still salvageable, but you definitely need to change their set-up, fast. Good luck!

Thanks for the advice- yeah, the worst of them is out of the sun now, so we'll see how it happens.