The GrayStone character also works fine.
I deleted the collision capsule and the AI Perception to make Twinblast the same as the ThirdPersonCharacter and still no luck. At this point I’m going to reduce the wall height and if that does not fix my problem, I will call it a wash and start over. I don’t see any other options.
I ran into a weird but similar issue, and one that might solve your problem…
When creating a wall with the new Cube Grid tool in the modelling tools found inside Unreal 5, it seems that it creates phantom, invisible meshes with full collision…ya, quite a bizarre side-effect
I had cut a hole into a Cube Grid block mesh, re-skinned with my chosen texture and for the life of me, I could not pass through the hole I had cut into it. It was driving me a bit batty, I have to say…
Then, reading this thread, I turned on the Collision view and there it was, not only one, but two complete, invisible collision meshes…quite mind-blowing really (I mean in terms of bugs, this is something else…)
Once I remove the two Collision fields, all was good, and I could go back to my game dev…
Hope it helps someone, somewhere 
Best,
Scott