Note: All previous "resolved" versions of this bug do not include any helpful resolutions for this issue. Extensive searching and debugging has been done. 

Running a vanilla server with people able to play. While the server runs overnight without any interruption, there is a point when other people cannot join or connect anymore. No errors in the log overnight. Localhost is able to run the world fine with no issues.

Recreating the server from scratch resolves the issue until the next day where the same thing happens. 

When starting the server, I get 

[13:01:40] [Server thread/INFO]: Preparing spawn area: 0%

[13:01:40] [Server thread/INFO]: Time elapsed: 896 ms

[13:01:40] [Server thread/INFO]: Done (1.502s)! For help, type "help"

Sometimes it jumps to 62% and ends there. 

Running the server on macOS Mojave 10.14.5. Java running latest runtime. Tested using several amounts of RAM and commands included in each "resolution" of each bug similar to this one. 

Included latest log from just now, and a log from overnight last night.