Fuck GWE !!! I'm just kiddin Kinger...well sorta ! NOT ALL COMPOST IS CREATED EQUAL !! TBS... it looks like the compost you're using isn't ready to use yet, especially on seedlings ! Basically two things can happen 1. If compost  isn't ready it will pull N from the media and the plant will suffer . 2.  The use of unfinished compost can burn the roots of your plant due to the heat released. Also "mushroom compost" has a high salt content so go easy if using that . Peace