There isn't any "surprised in" that I can think of. I Googled these and found that "in" was the beginning of a prepositional phrase that interrupted "surprise" plus some other preposition. I was surprised, in fact, to hear that ...
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They can be synonyms, but there is a shade of difference.
When you say
I was surprised by his behavior
it is the passive voice, like saying
his behavior surprised me, or
his behavior took me by surprise.
When you say
I am surprised at you
there is slightly more of a judgmental cast to it,
implying that you had expected better from him.