I've only had this phone for about a month but this has been a problem since day 1. When my phone is at high charge (roughly 60% or more) and charging the sound will cut out for just under a second up to every 5 seconds.
There's already a huge topic here : https://us.community.samsung.com/t5/Galaxy-S-Phones/Sound-problem-Samsung-Galaxy-A8-2018/td-p/292501
But all samsung have said in response is that they only deal with US customers.
Helpful I know.
So I've made an EU post to hopefully get a real response.