Created attachment 310642 [details]
Screenshot of Safari and Chrome (for comparison)
In the following example, all characters should be rendered sideways because all of them have "R" property of UTR#50.
However, the numbers (123) in the second line are rendered upright on Safari.
The problem occurs with Source Han Serif, but does not occur with Source Han Sans.
I found that the issue won't occur without "latin_special" lookup substitutions defined by:
It looks like this is fixed now. Can you check again?
Safari 11.1.2 (13605.3.8) looks good. Thanks.