I don't know if it really is a bug.

But I noticed that my ranger now lvl 5 still able to cast spells.

If I'm not wrong it's only possible when they are 6 right?

I can remember if I've some special item that allows me to do it, I think I don't.

Char: Vilae Dwin'lylth

Correcting:

I can't remember ...

With 14 wisdom as I recall a ranger can cast from level 4 onwards. I could be mistaken though.

That is correct, as it gives you bonus spells for that level, even though you don't get any actual spellslots.

Then how can my char cast?

Because I've one spells slot at lvl 5 and also I can cast.

So it's a bug then?

Ranger info As you can see, the Ranger class gains spellcasting ability at level 4. At level 5 that ability is unchanged, with a base value of 0 1st level spell slots.

Ability modifier info However, having a Wisdom score of 12 or more grants you bonus slots, as the table states. This will add to your base value (0) which results in 1 Ranger spell slot on character level 5.

Hope this clears it up.

Thanks then =)

Seems fixed.