Hi guys. There are a few concepts that I'm really confused by in checkraises pots. I remember watching Pete Clarke's key concepts video "After the Flop Raise", and in it BB bets almost range for a small size on turns that hit BB a lot, while polarizing and betting big on bricks where a lot of BB bluffs miss. For the record the flop in the video was A75r and turn was either a 2 or an 8 if I can recall correctly. On the 8 BB bets merged and in the 2 BB polarizes. So all of the above I understand clearly.

However I reviewed a hand of my own recently where I though the above concept would apply but according to the solution it's the opposite, BB polarized the turn hard and bet very infrequently.

The hand:

EP vs. BB (the villain was UTG but I tested the solution with HJ ranges as well in case he was loose).

UTG opens 2bb. I flat in BB with T8s.
Flop: 9c7s6d (HJ: 53% equity. BB: 47% equity)
BB: check
UTG: bets ~70% pot
BB: raises ~pot
UTG: Calls

Turn: 8d (HJ: 45% equity, BB: 55% equity)
BB: check
UTG: bets 33% pot
BB: Raise (I probably shouldn't have)
UTG: calls

River: 8h
BB: bets 10-20% pot
UTG: shove
BB: fold

I threw this in GTO Wizard and the turn is getting barrelled by BB very infrequently and it's an overbet. I'm confused because at first glance this seems contrary to Pete's video where a turn that favors BB (and equalizes equities) gets bet small.. For the record, if I change the opener's range to HJ, the equity shift is a decent bit less pronounced
on the turn but BB still polarizes turn.

Can anybody explain how this board is different to the example in Peter's video? Why are we polarizing turn? Vs. on A758 BB bets turn merged after a flop checkraise.

As a confusing aside, vs HJ is the only position where BB block bets river.

Thanks in advance.