First things first, thanks for developing this great app, it really saves my life from time to time! :)
Going back to the issue. After installing ACR on a new phone and copying over recordings I went to Settings/General and tried DB Maintenance. No records reappeared on the list, despite all of them are in ACRCalls folder, I double checked it. And despite I did the same thing a few weeks ago and it all worked flawlessly.