The deform parameter of the Bmesh from_object method is deprecated,
always assumed to be True, and will be removed in version 3.0.
That is because the cases where it is False don't work correctly and are
subject to memory leaks. One of the symptoms of the incorrect behavior
is the application of constructive modifiers twice if the input object
is an evaluated one, as demonstrated in D10053.
Reviewed By: Brecht
Differential Revision: https://developer.blender.org/D10086