Got a problem case.
Attached to
this post is an epub with image scaling tests for formulas.
There's two examples in there using object tags.
If you open the ToC in Marvin, the following two entries do weird stuff, Marvin literally tries to push these out of the device
SVG which should have a width of 1em (object tag)
and
Inline SVG which should have a width of 1em (span, object tag)
both example pages dive down, don't know how else to describe it.
That is, if the example uses the code tag too I think. Because there's an overview page at the end of the book using all of the methods combined but without the code tags and there the content in the object tags behave normal