Ehrlich's reagant goes blank for supposed LSD blotter, yellow for supposed AMT?

[rolodex propaganda]

I tested some LSD blotter with Ehlich's reagant from the Bunk Police. There was no color change when 1/4 blotter was used. The test was repeated twice. To make sure the reagant isn't faulty, I tried testing some AMT. The AMT went yellow...

Why would this happen? I thought Ehrlich's turned nothing yellow. Was I sent the wrong reagant? What would go yellow?

 

[sekio]

How old is the reagent? They don't keep forever. It sounds like it's just gone off.