Add the following line: deb http://apt.osmc.tv stretch-devel main
Run the following commands to update: sudo apt-get update && sudo apt-get dist-upgrade && reboot
Your system should have have received the update.
Please see if the issue is resolved.
I also recommend you edit /etc/apt/sources.list again and remove the line that you added after updating. This will return you to the normal update channel.
The improvements were mainly for Kodi’s built in SMB mounting. I just saw in your logs you are using fstab based mounts. There are also some CIFS improvements there too.
When you say crashing, I assume you mean playback is just stopping?
Can you try using Kodi’s built in SMB client to see if this helps temporarily; and can you clarify your SMB version?
Just tried to use the build in SMB client to watch a movie, this also didn’t work as the picture would flick on off suddendly. Not sure that is related though.
I think File Exists is an authentication error IIRC.
The playback stops because of an issue with SMB. It’s not clear what’s happening, but it looks like the connection is getting reset or dropping.