Found the root cause of this issue. OOB Vanity URL's were not working
because of internal sling mapping and dispatcher mapings. So as a
solution we implemented custom vanity url path by appending the
/content/site/locale path internally thorugh code and now OOB vanity
urls are working.
There were some known issue related to scrolling in column view not
loading all the items (when we have multiple items to display), but
that's for XF UI. It seems to be a product issue, please open a case
with Adobe team to check further.
OSGI does not support multi-dimensional arrays of values, but just
simple lists. When you need to provide more complex data as OSGI
parameter, you should consider to package the configuration in a
different format (e.g. as JSON file in the repository, or a node
structure), and use OSGI to configure the path to it.