If you have a badly formed BB-Code, yes, delete it. Island isn't supposed to have a BB-Code.
Malformed BB-Codes occur if you change a wiki code to accept an option parameter via the BB-Code Manager, or if you change the title, displaytitle, or BB-Code tag for a namespace after its initial creation. In this case the BB-Code gets duplicated the next time you save a namespace and only 1 version ever gets updated.
Fixed for the next build.