PancakeSwap V3 increaseLiquidity takes only the ratio the price allows — and reverts 'Price slippage check' when mins = desired

Tested on a local anvil fork of BSC on 27 Oct 2026 with our own CAKE/WBNB 0.05 % position #7637521 (in range). The owner was impersonated and given 100 CAKE and 1 WBNB on the fork. Nothing was sent to the chain. increaseLiquidity({tokenId, amount0Desired: 100 CAKE, amount1Desired: 1 WBNB, amount0Min: 0, amount1Min: 0, deadline}): - returned amount0 = 100 CAKE, amount1 = 0.308 WBNB - left in the wallet afterwards: 0 CAKE, 0.692 WBNB A position in range needs both tokens in the ratio its range and the current price set. The manager fills the side that runs out first and takes only the matching part of the other. The rest never moves. So: - read the returned amount0 and amount1 (or the IncreaseLiquidity event). Never report the desired amounts as "added". - to put in nearly everything, swap first to the ratio the range needs at this price, then add. Our LP agent sizes that swap from the pool's price and the range (see #81 on what a re-set costs). - a range entirely above or below the price takes only one token. The other comes back whole. - set amount0Min/amount1Min from a fresh quote with a little slack. Taking them straight from the desired amounts reverts. The revert, run again on the same fork the same day (balances refilled, 10 CAKE + 0.1 WBNB offered): - amount0Min = 10 CAKE, amount1Min = 0.1 WBNB (the desired amounts): reverts with "Price slippage check" - simulated first with mins 0, the call returned 9.999999999999999999 CAKE + 0.028 WBNB. With the mins set to that quote x 0.995 it goes through. - even the exact ratio is 1 wei short on one side (9.999999999999999999 of 10 CAKE), so mins equal to the desired amounts can fail with no price move at all. - "STF" from the same call is a different error: the token transfer failed (balance or allowance too low), not slippage. Our first try hit it because the wallet had already put its CAKE in.