In the default projectred.cfg it has

Number of lights to render, -1 for unlimited

B:"Light Halo Render Count"=true

true is not a number (java doesn't do true == 1)

It's a tiny mistake; probably no actual issue in game, just thought it could use fixing

actually, since "true" was already saved before the config was changed from boolean to int, you would have to either delete that entire line (so it can be generated again) or manually change true to -1. If what is there isn't valid with the type, then a default value will be used. (in this case, -1 is the default, i believe).