Cannot convert 1.12.2 world to 1.13 using "Optimize world" function

So I have a map file from my server, rather large in size, which I am trying to keep playing on after the update, After copying it to the single player saves folder, I have tried using the "Optimize World" function. It loads for a while, but each time, at 97% it gives the "Failed " message. The version on the map apperars, however to be changed to 1.13, but results in a crash when trying to load it. "stackoverflowerror" briefly appears on the screen before the game closes. 

The map file is apparently too big so I am going to include a link to download it.

https://files.fm/u/2uab8ubd#_