I was flying at 160 knots, as TFFR Tower told me to maintain slowest practical speed.
How to reproduce:
1: Open IF
2: Select any 747-400
3: Fly to an altitude of FL200
4: Start to descend to 3,000 at -1,500 to -2,000fpm
5: Slow speed to 160KIAS at 5,000.
A321 Version of IF