Fatal error: Cannot delete files/folders outside the current working directory

I was reading through this post, and I have the exact same issue on Kibana 6.4.3:

FATAL Error: Cannot delete files/folders outside the current working directory. Can be overriden with the `force` option.
    at safeCheck (/var/vcap/data/packages/kibana/18cc759ef9f7faf785ce8b87573928862ad26958/node_modules/del/index.js:18:9)
    at mapper (/var/vcap/data/packages/kibana/18cc759ef9f7faf785ce8b87573928862ad26958/node_modules/del/index.js:33:4)
    at Promise.resolve.then.el (/var/vcap/data/packages/kibana/18cc759ef9f7faf785ce8b87573928862ad26958/node_modules/p-map/index.js:46:16)
    at <anonymous>

However, in my circumstance, I cannot add the --force flag because Kibana cannot write outside of it's own directory. What is the cause of this error and what steps can I take to resolve it?

I continued to debug the issue (just enabling debug everywhere, and I found this:

{"type":"log","@timestamp":"2019-07-12T20:00:16Z","tags":["plugin","debug"],"pid":27183,"path":"/var/vcap/data/packages/kibana/18cc759ef9f7faf785ce8b87573928862ad26958/src/core_plugins/vega","message":"Found plugin at /var/vcap/data/packages/kibana/18cc759ef9f7faf785ce8b87573928862ad26958/src/core_plugins/vega"}
{"type":"error","@timestamp":"2019-07-12T20:00:17Z","tags":["fatal"],"pid":27183,"level":"fatal","error":{"message":"Cannot delete files/folders outside the current working directory. Can be overriden with the `force` option.","name":"Error","stack":"Error: Cannot delete files/folders outside the current working directory. Can be overriden with the `force` option.\n    at safeCheck (/var/vcap/data/packages/kibana/18cc759ef9f7faf785ce8b87573928862ad26958/node_modules/del/index.js:18:9)\n    at mapper (/var/vcap/data/packages/kibana/18cc759ef9f7faf785ce8b87573928862ad26958/node_modules/del/index.js:33:4)\n    at Promise.resolve.then.el (/var/vcap/data/packages/kibana/18cc759ef9f7faf785ce8b87573928862ad26958/node_modules/p-map/index.js:46:16)\n    at <anonymous>"},"message":"Cannot delete files/folders outside the current working directory. Can be overriden with the `force` option."}

So I think the Vega plugin is causing the issue.

You could maybe try symlinking the folders to fool the OS to think they are in the same working directory. It's a pretty weird issue, and without more information it's going to be hard to reproduce and troubleshoot.