Can't add block to footer (menu disappears)

I'm trying to add a block to the footer of my website (for a logo), but the menu instantly disappears. When I add a block to any other section, the menu is there to add a block. 

Has anyone else come across this?

Found the issue, you have to remove any custom CSS first for some reason, then add it back.

I'm having this same issue when in some sections on one of my pages. Some of them I can add a block and others I can't... 

23 minutes ago, Katey001 said:

I'm having this same issue when in some sections on one of my pages. Some of them I can add a block and others I can't...

Are you using a mix of Classic Editor and Fluid Engine sections or custom CSS as @paul2009 mentioned above?

Having the same issue. I click "add block" and the menu appears for a half second, the page then automatically scrolls to the top, and I have no ability to add any content to the page.

The only way I am able to add content is by copy and pasting blocks from previously created sections into a new blank section...

6+ months later and this is still happening, does anyone have a solution?