So now I have 2 R15's setup with 1 as a mesh extender, I also have a E15.
E15 shows solid white light which means connected, the second R15 also shows all good but in the portal of the main R15.. it shows 0 extenders..
Sometimes after like a day the secondary R15 will start showing no internet and will not work until I power it off and back on (will show up as an extender shortly, but then go away again).
All and all, still really buggy..