The party that goes to Forest Heart, looking for the Tain,
does so before the redemption of the Heron Guard. The
test introducing Redemption reads...
"The events I am about to relate occurred just a few days
after my departure to Forest Heart. In the interest of historical accuracy, I have inserted these pages in my journal to acknowledge this important moment in time.
After the Ibis Crown was recovered from the ancient tomb below Muirthemne, a ceremony was held to coronate Alric as the new Emperor of the Cath Bruig Empire. The journeymen, after a hundred years of self-imposed penance for being absent during the fall of the city, threw down the gold tiles that hung around their necks and swore fealty to the new Emperor.
The journeymen were no more; the Heron Guard were reborn.
Hours later Muirthemne was overrun by Myrkridia and the Heron Guard were given their chance at redemption. "
Given the above, how is it you have herons with you looking
for the Tain? Sure, they could have got their skates on
and caught up with you after defending the walls, but it feels more like a mistake in the story to me.