I flew into Gatwick last night and once again was rejected at the egate. I've pasted below a thread I replied to on Trip Advisor:

I have exactly the same problem with mine. For the last 2 years in the UK I've not been able to use the egates in the UK. When I asked at immigration last time what the issue was she said "I'm not at liberty to say". I asked her if my passport was faulty (as the embosser cover has worn off) but she said the chip still works, so I asked her again what the issue is and she said the same thing.....I'm not at liberty to say 😡. I'm pretty sure I'm not moonlighting as a terrorist but it's how I'm made to feel every time. To make matters worse, I'm disabled (although not in wheelchair) but had extensive surgery to both hips all my life and its physically painful having to queue all this extra time as of course you don't have the option to skip the egate, no matter how many times you tell them it won't work. Surely there must be some way to sort this issue out.???? I travel a lot and shouldn't have to be in pain due to their incompetence 😡.

And just to add, I don't think this is related to photo recognition as it doesn't even start the process. I immediately get the "seek assistance" message.
Some people have mentioned issues with some 2016 passports and mine was issued then.