Reported by @MartinPoulter on the glamtools mailing list:
I chose a category which includes an apostrophe character:
Files uploaded by the Bodleian Libraries' Wikimedian In Residence
The system renders this as:
Files uploaded by the Bodleian Libraries&
This is easy to fix post-upload with cat-a-lot or a similar tool, but it would be nice to fix it in code.