I had similar issue. It happened only on some tiles with Prefabs.
In the scene window, I only could see the tiles when editing, but once commited tiles dissapeared. When playing, prefab objects were right.
The only way I found to fix my tilemap:
-Edit the tilemap and delete those tiles, then commit.
-Edit again, re-add tiles and commit.
Now I see the map correctly on scene window, but I have seen this issue twice already....