Niko is missing in maps

Hey guys,
so a few days ago i began the mapping part. Problem is, I probably encountered Niko for Delve maybe 3 times? Haven't seen him (except master quest) since probably the level 76.. I'm nearly 86 now. It's been at least 10 levels of sorrow ( and 30-40 maps without him ). Anyone is experiencing the same "bug" ?

Niko, I love you, come back here! D: