i used a tea & a token i got from the gift box when i level to 51(i think) & the xp i got from defeating mobs is way lower than when i didn't use these items
from the screenshots i made, before i used those items, i got 166 item xp & 166 character xp from a target, after i applied those li xp items, i got 89 item xp & 138 character xp from a target, these are only 2 sample figures but the trend of xp gained is the same to all kills
Mobs of same level but less difficulty to kill give less xp/ixp, e.g. orc/goblin verses a crow. Or you were teamed/someone Helped you, both halve the xp/ixp you get