Recently I performed a calibration to match two different products of ROE modular LED panels.

I used a CR-100.

When matching the Primaries and Secondaries by the readings there was an obvious ( to me ) difference in color between the two products.

I matched by eye and then took readings again and the numbers were off dramatically.

What could be going on there, and how would I troubleshoot this ?

Using a colourimeter, without matching to a spectro on the different panels will never generate a calibration match.

Second, if the panels use radically different display technologies you will potentially hit metameric issues.

Steve