[SQLState 42601] ERROR: cannot insert multiple commands into a prepared statement Initial SQL Error

Referring to this question that was never answered by Tableau and causes me huge headache!

Quoting:

Can a developer from Tableau please chime in on this? I am getting multiple answers across the web on how to resolve this problem. The issue is encountered when choosing the Initial SQL option. I am pulling from a Redshift database.

My first inclination is that this is a limitation in Tableau which disallows the high character count in the Initial SQL option when populating my database tables. This is due to a post I read from this forum a while back (which I can't find now) stating that maximum characters allowed in the Insert SQL command was 30,000.

I believed this until this morning, when I am getting the same error message when I insert just a 300-line section of code in another workbook. I went through my code (which contains multiple temp tables) query by query, and finally arrived at the offending query. I removed it from the larger statement, and the query proceeded just fine. But now that I have added in another 15 or so temp tables into my overall SQL insertion, I am getting the same error.

Now the ridiculous part: Sometimes my entire SQL insertion will work just fine, for example if I open a clean desktop workbook and insert the code, it will work fine. But if I take that same code and replace what is in an existing workbook (where I have dozens of dashboards built), and I get this error every time. It's super inconvenient when I need to tweak the code in an existing workbook and Tableau won't let me due to this error.

What. Is. Going. On. What Exactly Does This Error Mean? I can run the query just fine in my front-end SQL development software.