I can't replicate it. But it is not only the starting button not working. I couldn't click on anything on the "Quest screen" too for once. But pressing escape let me back to the other menu and then I could click on those again when going back to the quest menu
Yeah I realized what was going on, some things were being saved properly with the new save system, so people coming from older version (myself included) wouldn't notice this issue, but new players that started on version 0.5.3 or 0.5.4 were probably getting this error.