Print buttons on order page not displaying/working properly

Hi,

Since upgrading to WC 3.7 my print buttons in the action column of the Orders page appear as blank squares. Clicking on them opens a blank tab instead of the print menu. Similar problem in the single order page although buttons appear normal.

I am running WP v5.2.2 and all up to date plug-ins. PI&DN is v4.5.1

Before contacting you I have done the following checks:
– deactivated all plug-ins to check for conflicts
– changed themes to see if problem was theme related
– checked in both Safari and Chrome

I noticed similar issues from other users that seem to have been fixed by v4.5.1. I am sorry to notice that this is not the case for us! Can you help, please?

Philip

The page I need help with: [log in to see the link]