@Fahad Syed Welcome to the Microsoft Q&A forum, Thanks for posting your question.
Can you try to set the search_path to app_schema,public from the application side__?__
Postgres would search an object (ex: ltree) first in the app_schema and if it doesn't find one searches the object in the public schema next. search_path can be changed by modifying the JDBC connection string or setting search_path connection parameters.
Please let me know if that can work.
Regards
Geetha