Add task button - problem

I have a problem when adding a new task, using the + button, while the board is still loading, after clicking the + opens the page with the image below, as if without css, I then have to go back using the back button in the browser to return to the board again, if I wait a moment and the board is loaded “will not spin anymore” when I press the + button the window for adding the task opens normally, which is how it should look. If I click the N keyboard shortcut it works fine, the white page does not appear.

Edit: clicking edit button on task when board is loading also show white page as image below.

Button that make the problem:

White page:

Example of a link that this white page has:

see also Broken view of add task - #2 by creecros