Lately, I keep hearing and seeing "embarrassed of..." used instead of "embarrassed by..."
It seems very awkward to me. You never hear "thrilled of you", it's "thrilled by you," so what happened to "embarrassed by you"?
Solution 1:
I think the correct preposition with "embarrassed" is always "by", not "of", even in the first of Saad Rehman Shah's examples. I agree with Kristina Lopez that this use of "of" probably comes from assuming that "embarrassed" works the same way as "ashamed". It doesn't really work the same way because there is a transitive verb "embarrass" but no transitive verb "ashame". (There is a transitive verb "shame", and I would consider "shamed by" correct and "shamed of" incorrect.)
Solution 2:
New Oxford American Dictionary (as bundled natively with macOS) offers nine definitions for "of". The most applicable appears to be the seventh:
preposition
[…]
indicating the relationship between a verb and an indirect object.
with a verb expressing a mental state: I don't know of anything that would be suitable | they must be persuaded of the severity of the problem.
expressing a cause: he died of cancer.
NOAD offers one definition for "embarrass", as a transitive verb (apparently now simplified to the denotation "with object"):
verb [with object]
cause (someone) to feel awkward, self-conscious, or ashamed: she wouldn't embarrass either of them by making a scene.
• (be embarrassed) be caused financial difficulties: he would be embarrassed by an inheritance tax.
It would seem then that the "embarrassed of" usage would be a mixing of a verb whose usage is exclusively transitive (expecting a direct object), with a preposition whose most relevant usage is expected to be intransitive (for an indirect object).
Thus, it seems to be nonstandard, but I personally feel the meaning it conveys is quite understandable.