World Partition HLOD Randomly Excluding Meshes

I have a simple world partition level, and inside it a level instance using OFPA and a variety of different objects.

Typically I see this issue with MergeActors-> Batch converted actors where the static meshes are ISM components.

Randomly some of the ISM components refuse to bake into HLOD, even though duplicates of that actor DO bake into HLOD. Its infurating, I have no idea why these actors with the same settings as actors that do bake down aren’t being included.

Here I have two rows of spheres. Both of these rows are simply an actor with 1 ISM component duplicated several times. They have the same settings.

One bakes to HLOD, the other does not. Why?

This is in 5.2

Nothing special being done on the actors after merge, I’ve tried assigning an HLOD layer manually but its the same result as if there was none assigned:

Still occurring for me in 5.3 preview.

I should note it seems like its related to the position of the actor being near cell bounds for the World Partition grid. Moving the actor away from the grid helps sometimes.

I can understand if its right on the seam between two cells, but even several meters away from the cell edge its failing to be included.