It’s absolutely not a problem. There’s nothing like the sinking feeling as you contemplate possible loss of data. The forum is here to help if anyone has any problems with Roon and all members are welcome to post at any time.
I believe the radio stations are stored in the Roon database, and computers being the noble but easily startled, flighty beasts that they are, it is always prudent to make a backup of the database and keep it updated. Remember to turn off the Core before making the backup, as a backup made with the Core running (with Time Machine for example) won’t let you restore from it (which is the whole point of being a backup).
It’s great to hear that things came right for you and please post again if this sort of bad state should recur. The devs can gather logs in order to track down the cause of such things. Personally I attribute it to cosmic rays and/or voodoo.