I recently found out that noteblocks do now attach to slime blocks.
I concider this as a bug because it wasn't in other versions. and will now attach to slimeblocks or stickypistons.
If this gets fixed i would be really happy cause noteblocks are far more beautifull then obsidian or any other blocks that do not attach to slime blocks.
Duplicate of MC-122362. In 1.13 note blocks are no longer block entities so, this is works as intended.