If you have changed the file association (setting Bandizip as the default app to open archives) but an icon provided by Bandizip for archives does not appear properly, a problem of icon cache in your OS may be responsible for it.
Try the following steps to solve the problem:
Settings (F5) ▶ Association ▶ Deselect All ▶ Select Essentials ▶ Apply Now
* The File Explorer of Windows is quite a complicated application, and the Explorer itself is responsible for a considerable number of issues which occur when you use third-party apps like Bandizip with it. If the same problem persists even after you try the solution above, make use of search engines to find other solutons to the problem like what you are experiencing.