Logic Pro 11.2.2, MBP M1pro Sonoma 14.7.2 Wave form edit eorror

my logic pro version 11.2.2,

OS Sonoma 14.7.2,

after update to latest version of Logic,

everytime when i trying to edit the waveform in Flex Mode (Polyphonic)

when i trying to cut/pull longer or shorter the wave form

it will either disappear or squeeze.

Do anyone have this problem and may i know how to solve it?https://drive.google.com/file/d/1MfNFPsyi4SwcPXRU0QdiI2SOnwEpqp5G/view?usp=sharing

https://drive.google.com/file/d/1kkqJhvnYfTdvjAD3ZlUZkRK0nlpAQdIN/view?usp=sharing