My fungus is still dying when exposed to light. I'm growing it on tilled soil from the Tilled Soil mod, and using a wall sun lamp from the Wall Light mod, if that helps.

ETA: It also happens if I try growing them in a hydroponics basin with the vanilla Sun Lamp.

Looks like the 1.6 patch added a new flag to the base cave plants that kills them in light, adding the following line to the current xml of this mod seemed to resolve the issue for me:
<!--set false die in light flag-->
<Operation Class="PatchOperationConditional">
<xpath>/Defs/ThingDef[defName="Plant_Nutrifungus"]</xpath>
<success>Always</success>
<match Class="PatchOperationAdd">
<xpath>/Defs/ThingDef[defName="Plant_Nutrifungus"]/plant</xpath>
<value>
<diesToLight>false</diesToLight>
</value>
</match>
</Operation>