Hi @Luca_Lattarini , this looks like an error in some custom code (or erroneous extension).
In particular it looks like someone is referencing a promise that has never declared (e.g. promiseEG.then(()=>...., by default promiseEG would be treated as a null object if not declared properly and the interpreter would be looking for a property of the object called "then").
From the screenshot, it would be within whichever rule usually fires just after the "All Pages - User UUID - Authenticated -10" rule. It's worth noting that whatever rule is using promises, you will not get the desired functionality on Internet Explorer since it doesn't support Promise.prototype.then().