Hello,
If IOU8 and IOU3/ASBR are in different VRFs on Juniper-1, then the Juniper-1 router won't advertise IOU8 routes to IOU3 and vice versa.
To make this happen, You need to configure BGP RIB-groups + perhaps "auto-export" and adjust Your VRF policies accordingly
HTH
Thx
Alex