run-cell shortcut not working in R Markdown?

[paul-grassl]

I'm working on a .rmd file (R) and I want to execute a whole cell of R code. But when using the shortcut alt-cmd-enter nothing happens. I checked with the Key Binding Resolver and hydrogen:run-cell shows up correctly and is green highlighted. Just nothing happens. Executing one line of code with cmd-enter works however. (also here the Key Binding Resolver shows hydrogen:run which is green highlighted)

In a .pmd file (Python) the run-cell command works on code cells, so I'm wondering if this is a problem with hydrogen and R cells?

Here are two small test files: test_rmd_and_pmd.zip