I have the same problem
my setup is 1) Raspberry Pi 3b+
2) ICS Pi 2x Controller board
3) 32 Gb San disk Micro SSD
1) OpenRepeater program version#2.1.2
The audio has a echo when in use but the voice announcements are perfect which would suggest there is a problem with the audio input.
The repeater has been working well with old logic board so i know the rx tx is all ok
Can you explain the setup in enough detail to where we can try to reproduce the echo? what port are you using, where are you hearing the echo, how loud is the echo, etc. the more details the better.
We have only ever heard about this one other time and were never able to reproduce the symptom. It is certainly possible there is a corner case, although the audio paths are completely separated except inside the audio codec chip.