Whilst I’ve had a Pi (model B) with a Pibow case from Pimoroni for a couple of years now, I’ve only recently started connecting it via ethernet and have noticed a minor issue with the “100Mb” indicator LED being non-functional, even when the ethernet connection is confirmed to be running at 100Mb.
A quick Google suggested a few other people with similar issues, and all seem to be down to R31 on the underside of the board being missing/damaged. Some of those reports mention that they are also using Pibow cases, and looking at my own it’s clear that the plastic edge of layer 1 of the case intersects slightly with R31, causing it the be sheared off when the Pi is mounted in the case.
Is this a known issue? Has it been resolved in more recent versions of the Pibow case?