Preview "are you sure you want to open x items?" alert

I am trying to open about 50 JPEGs in Preview and I am confronted with an alert asking if I am sure I want to open "50" items, Cancel or Open.

Happens on double-click. If I right-click and select open with Preview I do not get this alert.

Did not get this in High Sierra.

They open fine.

Just curious where I can get rid of the alert or change the trigger.