Video drop outs using VHS VCR composite video into STB/DVR input TX-NR616

I bought a TX-NR616 eight days ago. I updated the firmware to 0300. Mostly it works well, but I have a problem playing a composite video signal from a SONY VCR using the STB/DVR composite video input. The video periodically drops out for a second or two (does NOT happen when playing directly into the TV through a composite video input), Also, any slight degradation of the video signal, such as when pausing or rewinding, will cause the video to drop out. It appears that it is a problem with the processing chip or software being intolerant of any but the cleanest input signal, something that is not very practical, as video from a VHS VCR is never of the highest quality. Seems to me this should be fixable with a software update.