I have 2018 that loses its seat memory all the time, or almost all the time. Very frustrating. I use the #1 remote all the time, and almost the only driver. Drives me crazy. I am going to look for a way to disable the memory, but don't remember seeing that there is a way. I have got the manual out more than a few times and re-programmed seat to make sure I was doing it right, that the problem isn't me. Wants to lean me back all the time! Sort of glad to know it just isn't me, but wished I'd brought it up while under warranty.
And on the lumbar question.... I love it, use it fully inflated all the time... but I'm older and have some back issues so sitting slumped over does not work for me. I even have a little inflatable lumbar pillow I sometimes use on road trips to add more lumbar.