Chrome Version       : 70.0.3538.77
OS Version: OS X 10.14.1
URLs (if applicable) :
Other browsers tested:
  Add OK or FAIL after other browsers where you have tested this issue:
     Safari: OK
    Firefox: OK

What steps will reproduce the problem?
Initial state: Chrome running fullscreen on at least two monitors. 
1. In a Chrome window with multiple tabs, click and hold on one tab and drag it to move it to the Chrome window on another monitor. 

What is the expected result?
Tab is dragged across monitors and can be placed into another Chrome window.

What happens instead of that?
After dragging the tab away from its originating tab group, the tab is released and becomes its own fullscreen window and no longer moves with the mouse pointer. It is possible to drag the tab within its originating group to change its order/placement, but as soon as it is dragged away from the group, it becomes its own window and no longer moves with the mouse pointer. In order to move the tab to another window, the user must click and hold on the tab again, at which point the tab can be dragged to the other monitor and added to another Chrome window's tab group. It appears that a tab must not be part of a tab group when moving it to another tab group. Behavior is the same in incognito mode. This problem may possibly be related to the upgrade to Mac OS High Sierra, as it appeared shortly after upgrading. 

Please provide any additional information below. Attach a screenshot if
possible.

Screen recording of bug in action: https://www.youtube.com/watch?v=VqKC-s16rig

UserAgentString: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_14_1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/70.0.3538.77 Safari/537.36