This is only a partial answer. It rephrases the question.
If some object looks differently to two people one might say that that difference is not in the object itself but rather in the subjects looking at that object. Here is how Wikipedia describes primary and secondary qualities:
The primary/secondary quality distinction is a conceptual distinction in epistemology and metaphysics, concerning the nature of reality. It is most explicitly articulated by John Locke in his Essay concerning Human Understanding, but earlier thinkers such as Galileo and Descartes made similar distinctions.
Primary qualities are thought to be properties of objects that are independent of any observer, such as solidity, extension, motion, number and figure. These characteristics convey facts. They exist in the thing itself, can be determined with certainty, and do not rely on subjective judgments. For example, if an object is spherical, no one can reasonably argue that it is triangular.
Secondary qualities are thought to be properties that produce sensations in observers, such as color, taste, smell, and sound. They can be described as the effect things have on certain people. Knowledge that comes from secondary qualities does not provide objective facts about things.
The shape of an object by this definition would be a primary quality and so a "measurable aspect of physical reality". It could not be reasonably different to two observers. However, as the Wikipedia article mentions, Leibniz, Berkeley and Kant criticized this distinction.
An answer to the question, Can a material thing (being) have different shapes at the same time? would depend on whether shape is a measurable aspect of physical reality or not. If it turns out that it is not, it may still be pragmatically worthwhile to take the measurement.
Wikipedia contributors. (2018, September 23). Primary/secondary quality distinction. In Wikipedia, The Free Encyclopedia. Retrieved 10:33, April 29, 2019, from https://en.wikipedia.org/w/index.php?title=Primary/secondary_quality_distinction&oldid=860853529