<<I've got 190 ranks in winds and I'm not a bard if that help this make sense to anyone.
I'm surprised you were able to play a lullaby at all with those ranks... Bagpipes take a heck of a lot more skill than 190 ranks to play anything more than the easiest songs on, even as a Bard... They're the hardest wind instrument by a large margin, with the possible exception of a concertina. For comparison, with 360 winds and 497 Music Theory my bard can play a lullaby without difficulty, but also without excellence. He can only get up to a rumba before slight difficulty sets in.
Wearing armour may account for any differences, or changes to to Agility or Charisma if you have anything that buffs either or both of those. The cleanliness and repair of the instrument factors in as well.
Also, are you sure you were playing your bagpipes and not another instrument? Sometimes I forget to stow my instrument, or think I've stowed it but haven't because of RT or mistyping, and take the new one out in my left hand and end up playing on the one still in my right hand by mistake...
-Evran
* Prophet Hotoke Fuku-Nyorai snuck out of the shadow he was hiding in.
