View the sales invoice you just created (see below). It will contain the build-in theme’s total under (kg) column and the Test Footer Text, although not fully compliant as the <hr> did not produce the expected solid line above “…This is an example…”
In step #7, he said that the default theme was not edited. The only thing that changed was creation of a custom theme. And that now begins with the default theme code. The point of this bug report is that features stop working even when they have not been removed. Apparently, the fact that a custom theme is used is the trigger, not what its code is.
As per the topic below, themes are no longer going to be supported. What works today will continue working for foreseeable future but it won’t be evolving anymore.
Instead, I’m interested why are you using custom themes in the first place and what is Manager missing so you can move away from custom themes.