A more thorough explanation:

But see

But see is a signal that shows the cited source supports the opposite of what the author just said, although an inference is required to see the contradiction. It means that the source that follows indirectly supports a claim that is contrary to the claim just made by the author. Unlike "contra," which indicates a direct contradiction, "but see" indicates a very likely contradiction.

Example 1: The author writes, "The defendant was not at the scene of the crime." But see, the police report states that the defendant's fingerprints were found at the scene.

Example 2: The author writes, "The study found no correlation between smoking and lung cancer." But see, the study only looked at a small sample size and did not consider other factors that could contribute to lung cancer.

The examples illustrate how "but see" is used to indicate a contradiction between the author's claim and the cited source. In Example 1, the police report contradicts the author's claim that the defendant was not at the scene of the crime. In Example 2, the study's limitations contradict the author's claim that there is no correlation between smoking and lung cancer. "But see" signals to the reader that there is more information to consider and that the author's claim may not be entirely accurate.