Did you try this one? I’m interested if it happens with this work around or not. The automated solution seems to be at the end of the discussion
[31 Mar]
I can advise a temporary solution, although it has become permanent for me, moving from version to version, which I use myself https://forum.sailfishos.org/t/the-sounds-of-incoming-calls-sms-notifications-disappear/9496/17?u=comsorg