Squeaking sound when power is reduced

[pbt]

I have a problem with my Elite Suito:

It's a squeaking sound when power is reduced - e.g. on short descents on hills.
The sound occurred after approximately 9800km

Link to video: https://youtube.com/shorts/JdtrFtcuPyg?feature=share (sound occurs after 13 sek...)

Are there any suggestions for solutions (e.g. specific spare parts)?

Best regards
Peter Thomsen