Oreo notification sounds are late

[alex_ncfc]

Since upgrading to Oreo a month or so ago, I've noticed that I will randomly get a whole load of notification tones play all together, or just after each other. Note that these are not the notifications themselves, just the sounds that would normally accompany them. 

Oddly, when looking for a pattern, I've noticed that I tend to get them at 09:56AM each day (which seems very random!), or not long after I've plugged my charger in (this could be any time) 

What's happening here? Anyone else expeirenced this issue?

[Hardy66]

I observe a similar behaviour, at least.

When a calendar item is due, the LED light goes on immediately, but the tone is delayed between 10 seconds and a couple of minutes randomly. But the tone starts immediately after unlocking the display or if the display was unlocked already at the time of the alarm.

According to this link this seems to be an Oreo issue to be solved by the application programmer. Funny enough, I'm using the Google calendar app with the latest updates; I thought at least Google should know about Oreo programming ...

The notifications of my favourite messenger (Signal) are delayed a few seconds only, so I can live with it. But even here the light comes before the tone, it used to be slightly after the tone in previous Android versions.