Your working page has this line in the <head> area:
HTML Code:
<link rel="stylesheet" type="text/css" href="css.php?styleid=3&langid=1&d=1398494143&td=ltr&sheet=sidebar.css,widgets.css,tagcloud.css" />
And your non-working pages do not. It includes this CSS which effects the tagcloud size:
HTML Code:
a.level1 {
font-size: 9px+1;
}
a.level2 {
font-size: 12px;
}
a.level3 {
font-size: 16px;
}
a.level4 {
font-size: 18px;
}
a.level5 {
font-size: 23px;
}
So, either ask the modification developer how to add the CSS line to all needed pages, or just try adding that CSS to the additional.css template.