[Highlight] Fenced code partially broken with derekwyatt/vim-scala

[Huxpro]

vim-markdown supports fenced code highlight with in markdown.
the problem is that vim-scala syntax works well for filetype=scala but partially broken inside filetype=markdown.

It's reproducible for code like object ID { or def Foo() {.
I assumed it's something related to brackets since adding // } would revoke highlights below this line.

I think it might related to the dynamics of vim-scala/syntax here:

exe 'syn region scalaBlock start=/{/ end=/}/ contains=' . s:ContainedGroup() . ' fold'

I am not sure what's the problem so I fired issues on both side:
vim-markdown: #142
vim-scala: derekwyatt/vim-scala#157