Audio passthrough is broken on Rpi4 after upgrade to kodi-rpi-19.4-5. A downgrade to kodi-rpi-19.4-4 fixes this issue.
I see a lot of the following errors in the kodi.log, which are not present in kodi-rpi-19.4-4:
$this->bbcode_second_pass_code('', '2022-09-16 09:43:40.070 T:11 DEBUG <general>: ActiveAE::SyncStream - average error of 302.700892, start adjusting
2022-09-16 09:43:40.071 T:11 ERROR <general>: CAEEncoderFFmpeg::Encode - Encoding failed
2022-09-16 09:43:40.120 T:11 DEBUG <general>: Skipped 7 duplicate messages..
2022-09-16 09:43:40.120 T:11 DEBUG <general>: ActiveAE::SyncStream - average error 14.700892, last average error: 302.700892
2022-09-16 09:43:40.121 T:11 ERROR <general>: CAEEncoderFFmpeg::Encode - Encoding failed')