(Some) Open world and railjack missions take forever to load

[Portlalaland]

Some open world missions (including railjack) take forever to load. It used to be not like this.

1. This makes me missing the reward from first stage of Plague Star sometimes, or missing the entire mission (see video below).
2. Some is worse than other. PoE and RJ are not too bad, but OV takes about 3 minutes (see video below).
3. It doesn't matter if I were a host or not.
4. It doesn't matter if I set the mission to solo.
5. The speed is fine if enter the open world straight from my orbiter, but not from the gate.
6. I think it started happening around heart of deimos - railjack rework. 

Please investigate.