From this image you can see that the left one connected fine, but the right one did not.
No matter what I try with a wrench I can't get them to orient.
They always favor south, east, and up, and won't face the shaft north, west or down.

They should always to to favor the shaft they are being placed on, and the wrench should be able to turn them in all directions, not half of them.

Mod version: 2.0.2-1.19.2-0.5.0i-forge

Found a temporary workaround (and another related bug): if the half-shaft cogs are placed against another cog to the north/west/down then the sidedness is flipped; they will always face north, west or down, not being able to wrench them south, east and up.

Just noticed that this repo is for the flywheels mod, not the cogwheels. The link on the cogwheels curseforge page points to this repo, and should be corrected.

You can transfer the issue to the cogwheels repo, or I can close this and open a new one if you wish.