Yes, I have same issue. I owe v.1 and v.2 chromecasts and use it with latest SlingPlayer for Android on 3 phones in my home including Samsung Note 4 and S5 as well as Nexus 5 LG.
The icon comes on S5 (runs KitKat 4.4.4) almost everytime whether v.1 or v.2 is available to cast. It takes however much more time for Slingplayer to appear on Note 4 with previous Lollipop and new Marshmallow. Finally on 3rd Nexus 5 phone cast icon shows up everytime.
Seems like a issue related to the phone/android version, not chromecast version.
To avoid the issue and interruptions I use Google cast app on either phone to cast entire screen and then watch tv with SlingPlayer. I know this does not allow to use tje phone for anything else at the same time I watch TV but it gives me a piece of mind not to miss the moment during Euro 2016 finals at least. ;-)
Hope it helps.
I've been using the latest version of Slingplayer (you know, the one with the green screen of death) for Android marshmallow on the galaxy s7 edge.
That version has been able to connect to Chromecast v1.
Then I decided to upgrade and buy Chromecast v2, but now the connection icon is no longer present not the Slingplayer Android version.
Anyone having similar issues and have resolved this?