Very light sensitive mutation

In-game I have the ‘Very light sensitive’ mutation. When I am outside there seem to be two things going wrong. Either I get no debuff at all (even though it’s during the day-time and I’m in the middle of a field), or under the @-screen it shows a debuff (In the sunlight iirc) but even though it colors my stats red, it does not detract anything from them.

tl;dr: Very light sensitive (and maybe also light sensitive) does not work. The debuff is not applied, even though it does sometimes give the message that it is.

Is it different when naked?

No. The problem persists.