In service portal, when accessing a page containing date variables, the date picker does not show up
Release or Environment
Customized theme being used
Revert the theme in the portal record (sp_portal) to OOB theme
To check if the issue is related to Theme being used in the portal or CSS includes in theme or JS Includes, verify if the issue is happening in $sp.do (To do this, replace portal suffix in URL from /sp to $sp.do) or not. If issue does not happen here, please make sure theme and portal configuration is correct or if any customisations are present. If issue happens in $sp.do as well, other configurations need to be checked.