anyone else having problems with chunkloading it may be more apt to call it chunk sending rather than chunk loading because the chunks are there, they are just never sent to the client. requiring a server restart to fix.
I'm not having any issues at the moment. Try making the server vanilla for a bit and see if the issue continues, if it doesn't, remove your plugins 1 by one and when it eventually stops, you'll know what plugin is causing it.
If you're using a plugin to control chunk loading, like Ptweaks or NoLagg, try removing them. Thery're both known to not work correctly with 1.3.1.