Apologies if this has been already reported. It also probably comes under the existing umbrella issue CONF-6992

A user of our WIKI entered the incorrect code for embedding an image into a WIKI page (paramaters should be separated by a comma instead of a pipe):

!image.jpg|width=100|height=100!

However, round-tripping causes the |height=100 string to double.
I.e: on the first round trip the markup becomes:

!image.jpg|width=100|height=100|height=100!

on the next:

!image.jpg|width=100|height=100|height=100|height=100|height=100!

... and so on.

This eventually caused the embed string to balloon to a massive amount, which ended up causing other issues.
While I understand this is incorrect markup, it shouldn't result in massive amount of extra markup to be created.