Reason is AWS infrastructure, more powerful partner and the CE branch thats compatible with SC code. Switching to Lumberyard made a lot of sense actually.CIG appears to have tried to just break away from the actual deal and go with Amazon where they don't appear to have any limit on how many products they can ship. Maybe hoping Crytek wouldn't do anything. That's not how you do business. The announcement they were switching to Lumbyard was always iffy to begin with and remember wanting to know why. It's not like it's a huge change in engine for CIG. It's not like they're suddenly redoing the game in UE4 to get better options,e tc. A lot of the issues they would have would still be there. Networking is only part of the problem. That would help with the online part in theory. That doesn't stop people from falling through ships, things just not working, coding, etc. It's not like they're changing engines to produce a better and different game. So there had to be another reason they wanted to go with Amazon and try to cut out Crytek. Regardless of any financial issues they as a company were still there and actually getting better after their Amazon deal. It's not like Crytek was on its way out at the time. So what other reason for the switch? I can only think so they could release S42 without issues or maybe other products. Maybe spin Arena Commander or FPS module as their own games at some point. Their deal with Crytek likely wouldn't allow that without them having to cough up more money because it's an change to the original deal and not a brand new deal.
Falling through ships has nothing to do with Lumberyard or CryEngine.