With low decimals (< 6), this in scope line could return 0.
The next require check is vars.minBidDelta == 0 it will just accept to re-set the liquidator address but with the same bidAmount:
Liquidators can just back-run another liquidator to gain the auction. To fix this issue you can add 1 loanData.bidAmount + vars.minBidDelta + 1 or accept only grate the values params.amounts[vars.nidx] > (loanData.bidAmount + vars.minBidDelta).
