I am also on Mac High Sierra 10.13.3 with Chrome as my default browser.
All the button links within Local Flywheel stopped working for me this morning. I thought I must have screwed up my Flywheel when I failed to shut down properly last night. I reinstalled Flywheel and restored my site and it still wasn’t working properly.
I can confirm that switching the default browser back to Safari works. I then closed Chrome and set the default browser back to Chrome and tried the button links in Flywheel again and Chrome now works properly with Local Flywheel.
This is a very strange issue. Any idea why this happens?