Yes that is exactly what I said in the video and in my messages, if you hide a column it breaks the writes, and if you don't hide any columns then the data sends fine. In my use case, I was hiding columns to have other columns built off of the data from a source column via formulas. Building this end table for a sales team, so another use case for hiding columns was just to modify the views for them to remove data they don't need.
"Hiding the column might break the flow and we do not recommend doing that" I never saw this anywhere online. Having this in an faq or some form of documentation online would be helpful.