Hey,
I had this issue, now the second time in a different project (both 4.25 and 4.26), changing level via level streaming in play mode and the reflection captures are not getting loaded from the new level. This makes all the metallic (static and movable) and all the movable objects black. For the first time I have spent a whole day debugging and trying to find a solution without any success. What made the issue really annoying is that it was completely unreplicable, even within the exact same project. Meaning that even if I just created 3 new levels, 1 persistent and 2 sub-levels and exchanged them in play mode, it was working perfectly. But in my actual game setup it was always broken. It was a short deadline client project and it was feasible to use simple level loading with Open level, so I just transitioned to that. Now, this started to happen again in a completely separate project made with 4.25 and using open level was not an option, so I played around with it some more and found a workaround. I will share this now, because the last time I was digging online for hours and didn’t even see this issue mentioned anywhere.
So what worked was in the Level BP of each sublevel waiting 2 sec after Begin play, making the reflection captures hidden in game, waiting 0.5 sec and then resetting back to visible.