Currently there are two menu bugs that are affecting some Google Business Listings for some restaurants. The bugs relate to the menu url not being displayed in the knowledge panel and local search and the second being the new add menu section not being displayed in the restaurants account dashboard.
Restaurant Menu URL Not Being Displayed
This bug has been ongoing for the past six months. The restaurant is able to add their Menu Url into the account dashboard, but the menu is not displayed in search results and local listings.
Not sure how many listings are affected, but Google is aware and looking at a fix. The main cases I have come across for this is Asia and Europe.
Add Menu Not Available in GMB Dashboard
This bug relates to some restaurant business listings that seemingly do not have the Add Menu section enabled in their GMB dashboard.
The bug seems to be related to the listings category, whereby the listing has used a specific type of restaurant “Italian Restaurant”. The current work around is to switch the category to “Restaurant” at which point once approved the Add Menu section appears. The category can then be changed back.