Fresh install on Joomla 3.9.27, Maria DB 10.4.17, PHP 8.0.2. Each Category displays the following error:
Warning: Attempt to read property "id" on null in C:\xampp\apps\joomla\htdocs\components\com_jdownloads\views\category\view.html.php on line 326
Thought maybe it was something to do with the defaul Uncategorized menu, but I get the same error on a category that I made. This error does not appear in the download links or in the overview, only at the Category view.
Install log reports no errors.