Minimal project to show godot issue on an animation on a panel container inside a center container.

Godot: 3.4.1

Remarks Animation:

• 0s: the panel is visible=false and position outside of the viewport
• 0.5s: the panel is visible=true
  • flicker here for a frame
• 1s: position of panel is still the same outside of the viewport
• 2s: the panel ends in its final position

Screen:

godot-issue.mp4