Modern navigation suddenly renders differently - change to the worse

Hello,

I am building a site for a client. It's a modern site, but not a hub. We use MMD navigation with three levels deep.  Overnight, the navigation rendering has changed. It took me a while to figure out what I need to click and it is not a good experience. 

In the screenshot below, the vertical lines are the new visual element. Before they appeared, the whole row reacted to a hover or a click. Now, the mouse needs to hover over the chevron icon to open the sub-menu.

Also, the "Working here" entry should link to a page, but clicking the text "Working here" only closes the menu. In order to actually navigate to the link, the chevron must  be clicked.

This is totally non-intuitive and caused a lot of confusion. 

Can something be done to bring back the more logical behaviour of the whole menu entry being the hover and click area?