How to remove double sound when pressing keys on Casio PX-120 when connected via MIDI port?

Question

MIDI

Hello. I plugged in the piano and it turned out that there is some strange feature (FL Studio). The connection was made using a Chinese MIDI2USB adapter.
When you press the keys one at a time, there are no problems with sound reproduction - everything is reproduced. But it is worth pressing two or more keys at the same time, the problem begins. When you release the keys, the sound is played repeatedly. If we take the number of keys pressed as X, then X-1 pcs sound. from pressed. What is it: a feature of MIDI operation (never encountered this interface in practice before), a feature of program settings, a feature of Casio px-120 settings? How can I prevent sounds from playing repeatedly?