Hello,
unfortunately, when you use edit online, you will have to live with this. MS Office performs various modifications in multiple requests and each are "valid" modifications / updates on the node on their own right. Within a rule, you can not determine what actually has changed, so you can not react to that.
If you were using a Policy / Behaviour instead of a rule, then you could react to some context information and avoid execution in case a specific modification "does not interest you". Policy / Behaviour always requires activity by a developer / administrator - an end-user can not define these in contrast to rules.
Regards
Axel