I've used kdenlive for a few years now and it's a great open source program. I can't give enough kudos to the guys and gals who develop this software. One issue I've had since version 9.xxx is the screen grab with audio crashing.

I found a fix for 9.xxx by reading through the 7000+ line of avconvert man pages and found the solution to my problem.
Version 9.xxx worked great when I changed the encoding profile to use the correct device.
-f pulse -i default -acodec libvo-aacenc -vcodec libx264 -preset fast -threads auto
https://youtu.be/Fwg7XO5YZbA

But now in kdenlive 15.12.1 this encoding profile no longer works and results in a crash.

Any info on getting kdenlive 15 screen capture with audio working?

Maybe a separate tool would do the job as good or better: I'm using vokoscreen which is quite nice for screen recording and offers more control. Make sure you don't get to the old vokoscreen homepage, the new page has very recent release with many Bugfixes and improvements.

I setup an encoding profile using the following options and can record audio but the last 3-10 seconds have no audio. Maybe a bug in ffmpeg which doesn't record the last few seconds of audio on a screen grab.

-f pulse -i default -acodec libvo_aacenc -vcodec libx264 -preset fast -threads 0