Thingiverse can produce different results to OpenScad, and error reporting is non existent so debugging is extremely difficult.  Here are a few lessons learned.

Default Backend 404

This is the output you receive when there is nothing to render - i.e. no object created

Strings and Integers

OpenScad can automatically convert integers to strings, but Thingiverse can sometimes throw a wobbly.  This can result in a 404 page not found when generating a model.

Always use the str() function to guarantee something is a string.

Endless Recursion

Take care with recursion - if you see a Default Backend 404 report after a significant delay, this could be caused by an endless recursion.