Scheduled Switch On/Off feature vs. Fairphone 3, 4, 5?

[Volker]

AFAIK this function (at least the scheduled “switch on”) only works on FP3,4,5 running /e/OS.
See this topic:

FP5 sometimes boots unexpectedly

So when I shut down my Phone it should only wake up after I reboot it, right? Well, obviously yes, thats why you shut it down, you want it to be turned off. However, when I shut my FP5 down in the evening, my Alarm goes off in the morning (it shouldnt, tha phone should be OFF), and when I go into Settings › About, i can see Uptime is like 1-3 hours sometimes. Why does that happen? Is it a bug on Fairphones side or maybe from the /e/ Developers?