All items.aspx Page keep refreshing after adding SPFx button in command bar.

Hello 

I created one button using SPFx and added in Allitems.aspx command bar. Then I hide the new button using following code https://www.c-sharpcorner.com/article/how-to-hide-command-bar-menu-item-using-spfx-extension/  in same SPFx app.

Now whenever I open allitems.aspx, it is keep refreshing and after 2-3 times it showing blank page. Then I removed above URL code, but Allitems.aspx page is still refreshing. Any idea what is wrong I am doing and how to avoid refreshing allitems.aspx.

Regards

Avian