Looking at this banner... At the end of the banner content, we have the following inside a <script> tag:
$(document).ready(function() {
[...]
/* Hide banner outside of main namespace (and Main Page, for sites where that isn't in main namespace) */
if ( mw.config.get('wgNamespaceNumber') > 0 && !mw.config.get('wgIsMainPage') ) {
mw.centralNotice.bannerData.hideResult = true;
mw.centralNotice.bannerData.hideReason = 'namespace';
}
if (!mw.centralNotice.bannerData.hideResult) {
fundraisingBanner.show();
}
});It seems that we need to move the code that sets mw.centralNotice.bannerData outside the $(document).ready() function, so that it runs before alterImpressionData() is called.