Web App has one more URL after the page operation

Problem description: Leader: There is a Web App. When you use this function to enter this page and then return, there is a # behind this address. If you return again, you need to operate twice to succeed. Foreword: On the first day of today, I went to the post for an internship. The director lost a Web App question to me. First I make a Web App, but I use the ASP.NET CORE 2.2 framework, and then use Android S