The ability of the Mauryan working elephant to actually build things was removed with changeset rP23579.
In a forum post it was pointed out that the ability can be restored when the elephant gets its mahout.
> the mauryan worker elephant needs a mahout (some person sitting on it and controlling it). If this is done it also can get back its ability to help on building structures.
* [[ https://wildfiregames.com/forum/topic/37023-task-add-mahout-to-mauryan-worker-elephant/ | Add Mahout to Mauryan worker elephant ]] (6/Mar/21)
The mahout has been added with rP25666, all that is left is someone to make a patch and give the working elephant back its ability to build structures again.
For this patch, the aura of elephant worker was removed.