that code is a little convoluted for just preventing the camera from moving when the character jumps.
A simpler way to do it using character blueprint:
(8.5 is the height you want the camera to be relative to the character )
There is probably a better way to do it but this is just what comes easiest (quite similar to your own code i suppose just more to the point)
However in this case you seem to be planning on making a platformer of some kind, maybe you would be better off making the camera a separate actor that chases the character but isn’t attached to it, it’d give you more elaborate control over the camera since it would only do what you explicitly tell it to do.