One thing not mentioned yet in this thread I don't believe is that not all data on credit reports across each bureau are always equal. For example, I've got 23 accounts on my TU report right now, 22 on EX and 22 on EQ... EX and EQ are each missing an account, but they aren't even the same account. Then, in reviewing the account data on each report I can find differences. Several of my closed accounts are still shown as open, but only on certain bureaus where on others they are shown as closed. I've got a late payment on one account that is correctly represented on 2 bureaus but shown on the wrong month on another. I've got one other account with late payments (major ones actually) and only 2 of 3 bureaus shows the late payments where the account is perfectly squeaky clean on the 3rd bureau.
Put all of this stuff I just mentioned above together, and that's a recipe for 3 different scores as they are all using different data to arrive at the score. Interesting enough, my scores are still relatively close with EX 744, TU 749 and EQ 751. Unless you are comparing apples to apples with identical report data for each bureau, there are far too many variables in question when trying to determine why one bureau score is higher than another.
I do not have the same experience. Experian tends to be my lowest score (TU > EQ > EX), at least when it relates to FICO 8.
+1. It has been the case for me too.