I have had my BDP3 configured with a 1TB internal drive, one 4TB external drive and another 1 TB external drive for several years now. They are all bus-powered 2-½” drives and I have not had your problem, gbaby. So, I doubt that “overloading” is what’s causing the problem, particularly if the issue just started recently and you haven’t changed anything.
This sounds like another example where we are glad that Bryston offers a five-year warranty on digital products and provides such great service and support.