Tags are not rendered correctly

[tcpekin]

I have found two situations where tags are not rendered correctly. The first is when the tag has an underscore.

Here are a few examples:
In source mode in a title # #shopping_list -

In preview mode (editable) in a title -

Reading mode does render correctly -

In the body text I see the same behavior:
#shopping_list

Source mode -

Preview mode -

Reading mode -

I would expect that all three modes look the same.