Ah ah i don't want to send them an email, but i assume they're using fairphones with the bug, and they should be annoyed too and resolve this
About android, i can answer you (i was already and still know lollipop users), it is a specific fairphone bug.
Thanks for the filter advice, but actually it has nothing to do with spams. As a lot of people, for my work and personal life, i'm in messages loops i need to read and decide if i need to answer now, delay or ignore (can be emails, but it's true with events, slack, tasks, etc...). Expanding notifications allowed me to see the message in a glance, as they're usually short, take action and forget.
Of course i can adapt my way of using the phone, stack messages, keep all of them in mind not to forget to launch an app, and decide later what to do with each of them. Or the bug could be resolved, the original OS feature restored and the annoyance gone
I'm aware the FP team has other priorities like security issues, and everyone has his own "nemesis" bug. I just hope mine will be resolved before they show clock in charging screen when phone turned off...