I have an E70 3.0d which so far has behaved itself
The only experience of EGR/DPF issues has been one of our sons has a 3.0d Toyota Pickup most of his journeys are short which was the basic cause of his problem a drastic drop in performance. He/we cleaned the EGR first, it was clogged solid so solid it was a full day's work, not just the Valve but inlet manifold and several vacuum lines were clogged or restricted. We replaced the vacuum lines and really cleaned the rest put it all back and off he went for a test drive when he floored the throttle, he left a Black cloud like a special effect from Harry Potter movie :rofl
Less than a week and issues were back this time DPF light on Toyota explained that he had 2 glow plugs down and if a glow plug isn't operating it doesn't regenerate?? The Toyota solution, replace the Glow Plugs and DPF £££, we replaced the Glow plugs here and he had the DPF Professionally Cleaned he has covered around 40k since and no lights or issues. His truck always started first time every time and never showed a fault light until the DPF cried enough. His truck has a full Toyota history but as it never showed warning lamps, they just did the service and stamped the book? Now once a week he gives it a blast up the M23 and back which seems to keep it in good health plus I have the Toyota software on the laptop now so we can run a diagnostic now and then to be sure.
So long winded way of saying if BMW are like Toyota you must have all glow plugs operating for a Regen to occur