My textbook seems to be rather contradictory, need help clearing up.

My textbook, the Oxford AQA A Level Physics by Jim Breithaupt, had a question along the lines of "Which interaction is responsible for decay when pions are created?" and the answer was the strong interaction . However, it also states that kaons decay into pions, and kaons decay via the weak interaction as they're "strange". Isn't this contradictory, or am I simply misunderstanding?

What I'm asking really is whether pions decay via the strong and are created via the weak? Are we able to tell what interaction is responsible for a decay when only given the produce?

I'd really, really appreciate any help.