Excaped characters in query get lost using filter on hit list

If I use query with escaped characters, the query will be unescaped when I use any filter option on hit list. For example:

https://dokumente.ub.tu-clausthal.de/servlets/solr/select?q=mods.identifier:urn\:nbn\:de\:gbv\:104-

clicking on "book" removes "\" in query url.