sof [BUG] Captured signal is silent in TestMixerPlayback

Describe the bug Captured signal is silent in TestMixerPlayback Issue was found in: [ICL] 12_00_TestMixerPlayback16000Hz16b16b8ch Repro: 1/75

Topology Description: Mix 3 playback pipelines into one using Mixer component, loopback signal on external SSP connection, record signal on record pipeline with audio verification.

Topology:
+--------------------------------------------------+
| +------+   +-----+   +-----+   +-----+   +-----+ |   +----+
| | Host |-->| Buf |-->| Mix |-->| Buf |-->| Dai |---->|SSPx|
| +------+   +-----+   +-----+   +-----+   +-----+ |   +----+
+-------------------------^------------------------+    |  |
           ...            |                             |  |
           ...            |                             |  |
+--------------------+    |                             |  |
| +------+   +-----+ |    |                             |  |
| | Host |-->| Buf |------+                             |  |
| +------+   +-----+ |                                  |  |
+--------------------+                                  |  |
                                                        |  |
+----------------------------------------+              |  |
| +------+   +-----+             +-----+ |             +----+
| | Host |<--| Buf |<------------| Dai |<--------------|SSPx|
| +------+   +-----+             +-----+ |             +----+
+----------------------------------------+

To Reproduce Run tests with Diagnostic driver: 12_00_TestMixerPlayback16000Hz16b16b8ch Repro: 1/75 With options --playback-iterations=75

Reproduction Rate 1/75

Environment

Branch name and commit hash of the 2 repositories: sof (firmware/topology) and linux (kernel driver).
- SOF BRANCH: main HASH: 6c4f3ea42f0d04e9a421dd8325cdbc9be31056bf
Name of the platform(s) on which the bug is observed.
- Platform: ICL RVP
Test environment: BRANCH: master HASH: 4c2b56f9d4e4519a5fe456ea2ef33f166ea6a45d

Screenshots or console output

23:45:14.206       => Wait for Streamers to play out of data
23:45:17.355       => Stop playback and capture streams
23:45:17.495       => Free streams
23:45:17.685     => Free components
23:45:17.716   => Post-iteration cleanup
23:45:17.716   => Verification
23:45:17.716     => Topology Iteration 0, Playback Iteration 0
23:45:17.779       Captured signal is silent

23:45:17.779     => Topology Iteration 0, Playback Iteration 1
23:45:17.922     => Topology Iteration 0, Playback Iteration 2
23:45:18.078     => Topology Iteration 0, Playback Iteration 3
23:45:18.220     => Topology Iteration 0, Playback Iteration 4
23:45:18.361     => Topology Iteration 0, Playback Iteration 5
23:45:18.517     => Topology Iteration 0, Playback Iteration 6
23:45:18.658     => Topology Iteration 0, Playback Iteration 7
23:45:18.803     => Topology Iteration 0, Playback Iteration 8
23:45:18.959     => Topology Iteration 0, Playback Iteration 9
23:45:19.087     => Topology Iteration 0, Playback Iteration 10
23:45:19.227     => Topology Iteration 0, Playback Iteration 11