Anything that's not a "standard" base?
Depending on the airfield layout and surrounding terrain/noise sensive areas, some airfields may have modified circuit procedures to be used preferentially, with a "standard" circuit being flown only if circumstances require it.
Last weekend I was at EHMZ, an uncontrolled field with a camping directly under the approach 09. So you fly a final approach that's offset by 30 degrees until you're past the campsite. Your modified base may have been a similar thing.
If you tell us what frequency/airfield this was we might be able to tell you more.