A70 missing words during phone calls

[John334]

I using a Samsung A70 phone (from 15 May 2019) with dual sim installed each having their own operator.
After the latest update last week (21-7) the caller on the other side of the line is missing my words during the call.
It happens on using both of the SIM operators.
Samsung support advised to send the phone in for repair, however, it is returned unrepaired (fault not found)
Today I've had the same issue again. The caller on the other side mentioned it as "the first word is clear, hereafter the other words are soft or suppressed, till I take a breath and its starts again with loud to almost nothing".
I have to repeat myself so many times, it's really annoying now.
I can hear the other side loud and clear.

The official Samsung repair company (Dynafix) said I've to load the factory settings again and test in this way if an app is interfering with the voice call. The Samsung switch software shouldn't be used to restore the phone if the origin of my problem is caused by an app. And to install app by app to find the reason. This is almost an impossible task. 

I didn't install new apps lately, otherwise, the installed are updated regularly.

It looks like the latest update (installed 22 July 2019) does have changed something because I hadn't the complaints before.
I'm running now: PRR1.180610.011.A705FNXXU2ASF5
SW service provider: SAOMC_SM-A705FN_OXM_PHN_PP_0004

latest android patch: 1 may 2019

Does anybody else recognize or have this behavior too?