It seems that DITA-OT does not indent codeblocks that are inside example tags for PDF output.
It draws an indented box around the example text
The codeblock is not indented so that it fits inside the example box but is indented to fit inside the taskbody margins.
The left line of the example box runs through the code.
DITA has this structure
taskbody
context
p
Properties can be set by reading property files or by a task that explicitly....
/p
/context
example
p
This example.....
/p
p
codeblock
Some code
/codeblock
/p
/example
/taskbody