From what I could see this is different than JIRA issue [Link Removed].
All the selected nodes information seem correct until the NodeObject->Delete(Sequence) in SAnimNotifyPanel::DeleteSelectedNodeObjects().
[Link Removed]
[Image Removed]
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-68260 in the post.
| 2 | 
| Component | OLD - Anim | 
|---|---|
| Affects Versions | 4.21 | 
| Target Fix | 4.25 | 
| Fix Commit | 10733121 | 
|---|
| Created | Jan 10, 2019 | 
|---|---|
| Resolved | Dec 16, 2019 | 
| Updated | May 18, 2020 |