I have just installed 4.16 today, created a new project with no starter content. After it was created I created a new default map and saved it. In the content browser, the file size is 15.999EB?!? On a 1TB drive?
Also the date that it was created is 31/12/1??
It is strange for sure but what can you really do besides wait for the next hotfix to come out. Personally I would just recreate the map and if it happens again then you can either spend a day or two troubleshooting it or just ignore the little stuff like this and continue making your game. I have run into enough small bugs here and there that this stuff doesn’t bother me too much since I can still do everything my game needs.
best of luck.