Before

After confirming \log by pressing <Enter>

The backslash disappeared.
I cannot reproduce.
Environment
There may be some conflicts with other extensions?
Could you please provide your environment information as described below?
Thanks :-)
I considered if it may be plugin conflict, so I tested all my plugins and I found it is true.
The bug is caused by plugin kortina.vscode-markdown-notes.
I have uninstalled kortina.vscode-markdown-notes, everything works well now.
Most helpful comment
I cannot reproduce.
Environment
There may be some conflicts with other extensions?
Could you please provide your environment information as described below?