Angular CLI UnhandledPromiseRejectionWarning on fresh install - node.js

Question

I am currently trying to start a new Angular CLI (v7.1.1) project up though ng new ProjectName and it seems to work as usually. Then when i run the ng serve --open command it seems to end sucessfully, but outputs the following Warning/error:
$ ng serve --open
** Angular Live Development Server is listening on localhost:4200, open your browser on http://localhost:4200/ **
Date: 2018-12-06T20:40:39.900Z
Hash: b89537a5317a31d5ae15
Time: 4712ms
chunk {main} main.js, main.js.map (main) 11.5 kB [initial] [rendered]
chunk {polyfills} polyfills.js, polyfills.js.map (polyfills) 223 kB [initial] [rendered]
chunk {runtime} runtime.js, runtime.js.map (runtime) 6.08 kB [entry] [rendered]
chunk {styles} styles.js, styles.js.map (styles) 16.3 kB [initial] [rendered]
chunk {vendor} vendor.js, vendor.js.map (vendor) 3.67 MB [initial] [rendered]
ℹ ｢wdm｣: Compiled successfully.
(node:3844) UnhandledPromiseRejectionWarning: Error: Exited with code 3
at ChildProcess.cp.once.code (/~path/to/project/node_modules/opn/index.js:84:13)
at Object.onceWrapper (events.js:273:13)
at ChildProcess.emit (events.js:182:13)
at maybeClose (internal/child_process.js:978:16)
at Socket.stream.socket.on (internal/child_process.js:395:11)
at Socket.emit (events.js:182:13)
at Pipe._handle.close (net.js:616:12)
(node:3844) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). (rejection id: 1)
(node:3844) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.
I dont know why this happens since i am using a completly fresh install without touching the code angular cli creates.
Currently running ubuntu 18.04, node v11.3.0, npm v6.4.1 and angular-cli 7.1.1 (as stated)
I have also tried to remove and install the node_modules folder but without no luck. It looks like its the OPN file that causes the problem, but i am not sure why.
Anyone else having this problem?

Answer 1

Based on the comment from GCSDC, i figured out the problem, or at least how not to get the error/warning. it was because i was using --open which tries to open a browser on the webpage.. but since the server the app is running on is one i connect to though ssh (and tunnels the ports) it don't make sense to use --open and then we dont have the error/warning anymore.
Apperently this warning don't show up in angular-cli 6.1.5 which the prev. project i was working on was running.
Thanks again GCSDC! :)