Weird behavior, new LG external monitor….ideas?

I just received the LG 34” 5k2k monitor.

I am using an M1Max 14” MBPro.

When I connected the monitor (via Thunderbolt) to the TB port on the right side, the image was poor (blurry) and in the Display preference, I saw 2 new monitors connected, one of which was the LG 5K and the other was an “unknown monitor.” Trying to drag the monitors around to arrange them worked for the one labeled LG 5K but not for the “unknown monitor” and the maximum display resolution that I could manually select for the LG 5K was NOT the monitors maximum (5K) resolution.

When I connected the monitor via TB to one of the two ports on the right hand side, it showed up as one 5K monitor and the images are sharp.

This is obviously odd. Any thoughts/comments?

Off the top of my head … Thunderbolt and USB-C look the same but are not. Have you confused the designations on the various ports that you were trying?