Genshin fanbase has an united opinion about how Klee's ability is to create explosions using mundane everyday object. This one just took that one step further.
(Self-)Explosion resistance comes standard on the mad bomber package.
Based on Klee's profile, she's just really, really, REALLY lucky not to get harmed by any of her own explosives. Heck, she blew a whole workshop and remain unscathed: that's how she's gotten her Vision.