Cessna 152 auto-tunes COM1 to random frequency

Steps to reproduce:
1.: At YSSY, position Cessna 152 about 1nm back from runway 16R at 300 ft using active pause
2.: tune COM1 STBY radio to 120.9
3.: press ↔ button to swap frequency

The frequency swaps but one second later swaps to 133.95

120.9 is the ATIS for YSBK and I want to use COM1 to tune it.

However, as you can see from the steps above, COM1 decides to
auto-tune to something else, and it is also a random frequency that Sydney does not use to my knowledge.

COM2 does in fact work!!

Expected result: 120.9
Actual result: 133.950