Italic with inline code doesn't work

[Hi-Angel]

Steps to Reproduce

1. Open emacs like emacs -Q -l markdown-mode.el

2. Enable M-x markdown-mode

3. Type in the buffer

    *text `code` text*
   

Expected Behavior

Both text and code are italic. Having at least the text italic would be fine too even though not ideal.

Actual Behavior

Neither of text and code is italic.

Software Versions

• Markdown Mode: from Git on 2017-10-25
• Emacs: 26.0.50
• OS: Archlinux