I would say the sentence is not incorrect, but is unidiomatic and not broadly used because you don't need to use the progressive aspect of some verbs like to look, to know, to need, to like (or love), etc. The verbs themselves express ongoing state and using the progressive tense seems to be redundant.
The problem is the trend to use the progressive aspect of those verbs is getting traction recently and you can't stop people from using it. For example, some verbs in this state verb list are more broadly used in the progressive tense than others. In other words, not all the sentences marked as not correct are wrong. Some people seem to use it not only for progressive aspect, but also for emphasis. Those cases should be examined on a case-by-case basis.
In the linked Ngram Viewer, I could find a very small number of results for "was lookiong surprised" and none for "is looking surprised". Almost same result for is looking shocked,looks shocked,was looking shocked,looked shocked.
The verb to look could be used in progressive aspect when it becomes more dynamic as in:
I have been looking for you.
To look for here means to try to find (search for) the location of something or someone. To look in the above sentence is used in a more dynamic way than in "She looks surprised". The key factor seems to be usage of each verb and how close it is to a dynamic verb and a stative verb in which it is extremely difficult to draw a clear line.
Some people use "Looking good!" or "Looking great!" and they don't sound unidiomatic. I don't see any reason why the verb to look can't be used in progressive tense. Some uses will sound more idiomatic than others.