The TrimerTrip dataset of SAMPL7, like cucurbiturils from previous challenges, posed the largest challenge for participants, as judged by method performance. Specifically, most methods performed poorly at computing binding free energies for cationic guests with cyclic, aromatic, and adamantane based moieties. In addition, most methods were relatively inconsistent at predicting binding free energies of hydrocarbon chains of increasing length, but the AMOEBA alchemical binding free energy methods did very well predicting 7 of 8 within 2 kcal/mol. Both of the best performing methods here used alchemical free energy calculations. Predictions from the best fixed-charge force field submission, based on nonequilibrium free energy calculations (FSDAM/GAFF2/OPC3), had errors above 2 kcal/mol for 8/16 host-guest systems considered. In contrast, performance with the AMOEBA polarizable force field and alchemical methods was significantly better here, suggesting that one key source of error may be polarization effects and/or multipoles.