A withdrawMode == 3 skips minting protocol fee
Note that when withdrawMode is 3, the burn function skips minting the protocol fee:
// Mints protocol fees. In emergency case, skip it with withdraw mode.
if (params.withdrawMode != 3) {
params.totalSupply = (
_mintProtocolFee(params.totalSupply - params.liquidity, _newInvariant, priceScale)
);
}SyncSwap Labs noted that this behavior is intentional.