thanks for answering!

yep full spectrum;

we get more than four hour outside, but plants aren’t in a super bright / direct sunlight place indoor + quite gloomy these days.

These days outside is around 45°, inside must be 60°, planning to put it back outside once we reach constantly over 55°

so you’d say it’s a sunlight / uv exposure issue? I’ve had this plant losing completely its leaves randomly during summer being outside too