13
No, there are no corrupt files. It is just the way how XOOPS textsanitizer works. To get rid of the problem, you will have to avoid using <{$xoops_footer}>.
I have an ampersand in a site description. XOOPS sextsanitizer would convert & amps; into & every time I made a change to the site description. Because of this, I could not get my theme pass the W3C CSS Validator.