I am using Kdenlive 17.12.3 on Zorin 15.2 I have mp4 video and a separately recorded audio track. When I try to sync the two tracks, I am able to use Set Audio Reference, but when I select the other audio track and try to use Align to Audio Reference, the option is not available. Any ideas as to what conditions would cause this? I've looked over the various posts but do not find this has been asked. Thanks

Audio align should be fixed in 19.12.3. BTW Kdenlive version 17.12.3 is not maintained anymore.