Okay Tom
I’ve found something and this may surprise you because you do appear to believe otherwise based on past posts. Anyway this is what I found. If you go check my test site you should see the white space grows under the footer widgets between 768px and 1024px whereas either side of that it does what it should. The position is correct.
The only difference/change I made was adding standard wordpress text widgets to replace the default text. That’s it. Before I did this we both agreed it was working right whereas now its not doing what it should be.
I can also replicate the same result on my primary staging site with or without everything activated. Its not related to the community v1.3.34 theme, plugins, cache or css. I flushed the cache, removed all plugins and css bar the code you provided above. Its something to do with the footer text widgets and or the css you provided or a combination of both. It cant possibly be anything else unless I have forgotten something you can think of.
I hope you see what I mean and can send some css and or reason why this is happening and how it can be overcome so I can add it to my staging and test site and check it works in both.
Cheers