I have the EXACT same problem.
1 Reolink Doorbell POE
2 DUO3 POE
New installation. Router, POE Switch (TL-SG1005P) with just the 3 cameras plugged.
Every day at aprox 18-20h, one camera, or the other, or first one then the 2 of the DUOS (the dorbell has always run smoothly) goes down and...