To render a table there must be at least 3 hyphens

[dharmaturtle]

First Header	Second Header
Content Cell	Content Cell
Content Cell	Content Cell

First Header	Second Header
Content Cell	Content Cell
Content Cell	Content Cell

But two hyphens renders with your previewer:

https://jbt.github.io/markdown-editor/#c8ssKi5R8EhNTEktUqhRCE5Nzs9LgfK5dJEBUFZXl8s5P68kNa9EwTk1JwcogszFJwcA

Also, I just realized there's a previewer built right into this Issue submitter form. Heh.