Submitted by bin2chen, also found by adriro
When openPosition(), we need to record the current feeGrowthInside0LastX128/feeGrowthInside1LastX128.
And when closing the position, we use Base.getOwedFee() to calculate the possible fees generated during the borrowing period, which are used to pay the LP.
openPosition() -> Base.prepareLeverage()
From the above code, we can see that the final value saved to liens[].feeGrowthInside0LastX128/feeGrowthInside1LastX128 is directly taken from UNI_POSITION_MANAGER.positions(tokenId).
The problem is: The value in UNI_POSITION_MANAGER.positions(tokenId) is not the latest.
Only when executing UNI_POSITION_MANAGER.increaseLiquidity()/decreaseLiquidity()/collect() will it synchronize the pools feeGrowthInside0LastX128/feeGrowthInside1LastX128.
Because of using the stale value, it leads to a smaller value relative to the actual value. When closePosition(), the calculated difference will be larger, and the borrower will pay extra fees.
Due to use stale feeGrowthInside0LastX128/feeGrowthInside1LastX128, the borrower will pay extra fees.
The following test  code demonstrates that after swap(), UNI_POSITION_MANAGER.positions(tokenId) is not the latest unless actively executing UNI_POSITION_MANAGER.collect().
Add to Swap.t.sol:
After LiquidityPosition.collectLiquidity(), execute Base.prepareLeverage() to ensure the latest feeGrowthInside0LastX128/feeGrowthInside1LastX128.
wukong-particle (Particle) confirmed
