Aircraft pitching up and down at a specific interval during descent when using spoilers.

[ApocalypsePlease0]

It happened on 3 flights I did, EDDM-EGLL, EGLL-EDDM, and KORD-KBOS. 

It was happening when descending in the managed descent mode while using spoilers, it doesn't seem to affect open descent, at least it didn't the one time I tried it.

Video: https://drive.google.com/file/d/1Ksf96TMlqlFh4ssE-R0hgkM5Nc-jm65E/view?usp=sharing (download for better quality)

Edited February 26 by ApocalypsePlease0

[DroneSim]

Simple, you are over 3000ft above the descend profile. The aircraft is already at maximum managed speed range. So it tries to pitch up. Then it remembers that it's still high on profile and pitches down again. That's my guess. I would use open descent in this case.

[ApocalypsePlease0]

1 hour ago, DroneSim said:

Simple, you are over 3000ft above the descend profile. The aircraft is already at maximum managed speed range. So it tries to pitch up. Then it remembers that it's still high on profile and pitches down again. That's my guess. I would use open descent in this case.

You described what's visible in the video, yes. However, that's not normal behavior and using OP DES is not the solution.