If you see status after doing chart, you may see that avilalable in General quota & WL in Tatkal. I guess sometimes current reservation availability is shown instead of showing "CHARTING DONE" when you queries for Gen Quota, if you see this again please see current reservation avaiability also - whether it is same as gen quota availability or not - it may be same. Maybe gen quota was WL actually but after doing chart current reservation status was shown instead of CHARTING DONE when you queried for gen quota. Gen quota available & tatkal WL may be also happen for ##WL/ Available for gen quota. You may also see gen quota wl, tatkal wl but after doing chart you may see again for the same train, same journey, same stations pair, same direction as: Gen Quota : CHARTING DONE (Earlier ##WL), TATKAL: CHARTING DONE (Earlier CKWL), Current Reservation: Available (Earlier:...
more... no data because not opened). I guess, in this case, current reservation seats come from some of unused seats of non- general, non- Tatkal quota (maybe even after giving seats to WL passengers for respective stations pair). Don't forget sometimes, there may be no room for current booking even in the time of opening of current booking.