Spotify and Youtube are third-part plugins, developed by community members. I’m afraid the dedicated support can’t do much about them, not being part of the core system.
Anyhow, the Spotify plugin has been re-written from scratch, it is currently under internal testing. The library used in the previous version was not maintained anymore, it was impossible to make it stable.
The new upcoming version should solve all the problems you mentioned.
Regarding Youtube plugins, if you have problems with them please describe them in the dedicated thread.