Crash report:
First visit to Ginger Island (unlocked it the day before), I made it three rooms into the volcano dungeon, then it got late so I came outside to sleep immediately outside the cavern entrance in one of the tents I'd got from the forest giftbox in front of Leo's treehouse. Before the save could happen, I also got the 'lightning strikes abandoned JojaMart' cutscene, then as soon as the screen faded to black, the game completely crashed.
I relaunched it, hoping I might still be on the island, but I was back in my bed in the farmhouse, with none of the items I'd obtained on the 'lost day', so I quit immediately without saving in case the save file might give some clues, but the timestamp on it means it's from the end of the previous day. I do have an error log, though, so I've attached that to this post.
Windows 10 (through Steam)
English language
Single Player
No mods
Of possible relevance, this is what I'd done on Ginger Island before the crash: Fed Leo's parrot and obtained about 3 or 4 more golden walnuts elsewhere. Obtained the mummified frog from the weeds in the forest, and picked up the package of 3x free tents (one of which I used to sleep in before the crash). Can't remember exactly what (or how many) monsters I killed in the dungeon (several hot heads, a couple of lava lurks, a couple of magma sprites and tiger slimes), but I made it about 3x rooms in. I broke 3 or 4 containers and picked up one magma cap, and I stepped on one pressure plate in the third (I think?) room.
Update: It appears that it might be related to sleeping on the island when that cutscene plays. I just re-played the day as best I could, then used a warp totem to get home so I could sleep in the farmhouse bed. No crash that time.