Hello Giblet,

when you are grouped with a higher level character your XP rate suffers significantly as described by you above. This is by design.

The same effect applies in a bit more limited manner if you are not grouped but receive assistance, for example your low level character attacks a mob and damages it, then your highlevel character kills it. The lowlevel character will not get full credit for that kill. It is the same for healing as well.

This effect stops once the level difference is sufficiently small. I forgot the exact value but it is something like 5-6 levels.

Cheers, Steph.