Better of course, to stop sooner. But if your battery is not a total train wreck, no harm.
What I mean is good cells can do this many times. A bad cell was a train wreck from the beginning, and discharging that low could be the last straw for it. So unlikely you damaged anything, and no you tested it. Next ride, you will know if a cell died pretty quick. If that does happen to be the case, nothing you could have done would have saved that bad cell.
What is very likely though, is discharging the battery to cutoff drives the cells out of balance some. I found it good practice to do a bit of extra charging before the next ride, or at least before the next long ride.
Charge till its full and unplug from the charger. wait half an hour, and plug it back into the charger. If it does not start charging, ride around the block and try again. This will give your bms an extra chance to balance the battery, getting all the cells equally full. Each time this is repeated, the bms gets another opportunity to balance it better.
Winter is coming,, over the winter, recharge the battery monthly or so. This gives it a better chance of remaining in balance till spring. Too long storage will result in the bms drawing enough power to unbalance the pack. Typically, bms runs on just one or two of the cells, so it can discharge those two cells in a half a year.
