@mikeyww, support requests aren't allowed here. Please post your question with full details athttps://support.mozilla.org/en-US/questions/new/firefox/form.
That may or may not be the intended behavior. You could file a bug at https://bugzilla.mozilla.org/enter_bug.cgi/ and see what they say. If you do, please post the link to it here.
While waiting for implementation, consider the Switch To Previous Active Tab & Reload All Tabs (https://addons.mozilla.org/addon/switch-to-previous-active-tab/) add-on.
While waiting for implementation, consider the Switch To Previous Active Tab & Reload All Tabs (https://addons.mozilla.org/addon/switch-to-previous-active-tab/) add-on.