After the OTA update, Just wanted to report after over a week my lines have not disappeared! Good news!Still have the lines! I now I have some new phantom proximity alerts - will have to check placement of spare. Maybe the update increased sensor sensitivity.
Not so good news- I am getting proximity phantom alerts that I believe are due to the spare tire positioning. I have noticed on hot days that I get the alerts, but on cooler days I do not get phantom alerts. Perhaps (?) the expansion of the tire during warmer days is just enough to set off the sensors?