I’m using Unreal 5.3.2, not sure whether this behavior is replicable in other versions. Long story short: been working on a Control Rig and, as I was about to put the finishing touches on it, I decided to take it for a spin and actually test it on a level. Going through the motions and actually baking some animations with the Control Rig. Found two bugs, which are kind of interconnected as far as I can tell. One of which someone already mentioned (Control Rig Controls Missing from Sequencer) in October last year, but got no response, and another I didn’t really find mentioned and took me a few days to debug and solve.
Bug #1: baked animations were not keying certain controls in my Rig.
I went through the blueprint code and checked and rechecked everything and couldn’t figure out what I was doing wrong. Turns out, I wasn’t really doing anything wrong: certain controls can silently fail during baking and the engine doesn’t explicitly tell you (AFAIK) except the control has no keys on its track at the end of baking. The solution I found for this is to rename the control. I have no clue how the control came to fail and require this workaround, but it might have something to do with the second bug.
Bug #2: certain controls can have their tracks in Sequencer disappear.
This is the bug I mentioned someone had come across (Control Rig Controls Missing from Sequencer) in October. I was renaming some controls and, suddenly, the track for one of the controls wouldn’t show up in sequencer. Turns out, I renamed a control to a name previously used by another control. To repeat myself from the post I made to the original topic on this issue: I had two nested FK controls, spine_01_ctrl and spine_02_ctrl. However, they were incorrectly numbered and 02 needed to be 03 and 01 needed to be 02. Renaming spine_02_ctrl to spine_03_ctrl went fine, no other control had been named that in the hierarchy yet. But when I renamed spine_01_ctrl to spine_02_ctrl, its track in Sequencer wouldn’t appear. I suspect, internally, a conflict happens and the system detects that another control has had that name before and the track for the control doesn’t appear. The solution is also to rename the control, this will bring the track back.
Thought I’d leave this message here for posterity.