Was this an ILS or NPA? I've had false glide slopes, but they've all been above the real one not below. Is that possible? It was CAVOK, but darkness, so they should have been visible with the runway. If the a/c descended to such low height too early was this a case of WTF is it doing now, and not reacting as we hope most would do, and disconnect and fly the damn thing into a safer place?
I see the primary approach is ILS. The chart has Altitude - M conversion tables, but DME linked in. The approach is 1977'agl at 8.5nm - 1647' at 6.5nm and descend from this at 5nm. So 400' at 8nm, if it was radar to ILS, is astonishing. Does Moscow radar ATC not have a 'low level alert' warning for arriving a/c? If this was a VOR approach does EK or AB SOP's not require a DMA v ALT check during an approach. Is this shades of the AC Halifax incident?
If this scenario is true is does seem scary that such a sophisticated a/c, in visual conditions could be at 400' all when it should have been about 1900'.
If it was at 1977' and the crew watched and wondered while it descended to 400' is curious. If at 700fpm that takes 2 minutes. That is along time to watch something you should not be happy with. A simple ALT v DME would have alerted you at the first check.
The comment that it failed to descend at the correct point on the 2nd approach is also worrying. Is this an SOP mess-up, a mis-understanding of how the system works, a system mess-up? What did they do differently on the 3rd approach?