The answer is NO, there is no one easier test date. The college board, and for that matter the folks at ACT, are very careful to make sure that the relative difficulty of different test dates is about the same.
Do some tests appear to be easier for some students. Absolutely. But with hundreds of thousands of students taking each test, some people are bound to think that a particular test is easier.
Even if one of the tests is easier, it will just raise the curve on which the test is scored so that you will need fewer wrong to get the high score that you want.
Don’t try to figure out which test is the easiest. You will only end up wasting time and energy that you could put into actually preparing for the test. Instead, focus on figuring out the right time for you to take the test so that you are as prepared as you can be.