How come I'm sometimes seeing a stripped version of a Jira ticket?

Question

Every now and then I go to my notifications, click on a job and find a ticket with the layout stripped back. Tagging people's names and inputting links shows me the html workings, instead of the normal polished look & feel.

Does anyone know why this happens, or a way around it? It's less fluid to work in.

Here is an example of what the comment box looks like:

unknown · Answer

Oh I see – actually I think what I'm experiencing is a bug, as I've clicked into the ticket twice and it's appeared differently both times.

Here's what the top of a plain text ticket looks like:

As opposed to the normal view:

Bharath Kumar Kappala · Answer

Well that is the icon for the issue type if you are a admin you would have option to make changes to the icons that the issue types use

unknown · Answer

Thanks for replying! It seems I don't have the same options you're seeing.

Though I've just noticed a clue in the notifications section that is only appearing on the plain text ticket issues, have you seen something like this (grey square + circle)?