Menu parent arrow issue

Normally parent menu items have an arrow icon that indicates the item has children.

My site has two domains pointed to it but the arrow doesn’t appear if you’ve come to the site thru the domain that is NOT the WordPress address in the General Settings Menu.

Otherwise the site looks as normal and once you select any item the problem disappears.

See what I mean here: https://www.ageingwelltogether — menu arrows don’t appear

https://www.nscommunitylinks.ca — menu items do appear.

Thanks for any help.