According to my notes here I tested the FM6126A code on an ESP32 circuit with a latch. Now I remember that on recent boards - not yet published, sorry - in anticipation of supporting panels like this I added a manual CLK pin that can be toggled while the latch pin is high and otherwise blocking the normal CLK pin.
You can find this mentioned in the code #ifdef CLK_MANUAL_PIN
You’ll need to add this pin and attach it to pins 3 and 5 on your circuit, and that will fix the shifted columns/address column issue you’re seeing.
I’m glad you pushed through and found a fix. I updated the wiki to help the next person with this situation, and to help with my memory as I didn’t remember that there were complications with the latch.