Why failing to get notifications of Stackexchange app in Notification Bar of Andoid 6.0? I receive no notifications of Stackexchange -app in Android 6.0 and/or CyanogenMod 13 in Notification Bar. 
Confirmed that the bug is existing also in Android 6.0 [MarkCh]. 
Characteristics


not phone dependent because I can reproduce the problem in two CM13 in two different phones
OS independent, since occurs in stock Android 6.0 and CM13 
likely Stackexchange -app specific  
not internet gadget specific (Pebble, Xiaomi Mi Band 2)   


Fig. 1 Stackexchange app in App Notifications, Fig. 2 Notification Access view without Stackexchange app, since I cannot install it




I contacted the developer of the application by email. I also voted with one-star the application to raise awareness about the problem, which has been now more than one year in the application with Android 6.0.  

Phone: Oneplus 2, Samsung Galaxy S4 gt-i9506
OS: Android 6.0, Cyanogenmod 13 official nightly, CM13 Temasek's Rom
Bug of the application with some hardware in Android 6. Update OS to Android 7 or 8 which are better supported.