The attached world has, for some reason, has no ticks (you can easily check by igniting tnt) and can't be saved. I don't run into this issue with other worlds, maybe because I haven't dragged them trough almost every snapshot since 1.13.

As this is a potentially harmful bug capable of destroying worlds it should be fixed as soon as possible.

 
(World is too big for Jira, so here's a Drive link)