I’ve heard inverse used to mean reciprocal often enough. And it’s technically accurate - a reciprocal is a multiplicative inverse. The problem is mainly that “inverse” is ambiguous, especially in this particular case (an inverse square root is a square!), whereas “reciprocal” is clear and unambiguous. Online you can find lots of uses of inverse, and questions about inverse vs reciprocal. So yes reciprocal is the better, more clear term to use here, but “inverse” to mean reciprocal does happen.