Should I worry about root over growth and disease?

[Quarinteen]

Hello all. I have another fun questions for you pros out there. The roots of my soil plants have started growing out the bottom of the pot. I trim them, but I noticed today that they were turning brown. Is this normal due to oxygen exposure or is there something bad starting?

[Quarinteen]

So a bit more info about the pots. I purchased larger pots than the ones they are growing in and they have elevated bottoms. I got it in hopes to avoid potentially bad situations like root rot. I never clean the bottoms. Could that be causing this?