is obvious is the present tense, and haven't read is the proper form in the second part of the sentence because it refers to a past action.
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Nina_NiaI used present perfect in this sentence as the result is 'obvious' and probably important at the moment of speaking.It's obvious that you didn't /haven't read the report.You are giving to much weight to the word "obvious". Both versions are possible, as already discussed earlier in this thread.