I don’t think it s a memory problem, I’ve tried with a map of 4 props, it’s similar.
It happens since I m using level streaming, it’s the first time I use it tho and I ve proceed like shown in the UE Doc: Trigger sublevels from the mainlevel BP, nothing more, I m using sublevels inside sublevels too like i ve got an hospital interior level inside the “area1” sublevel.
And I ve got a new problem, before, I was able to move after picking up an object and if I went out the trigger box and back, the level was called again but now, without changing anything, It’s like it disable all inputs right after I pickup the object…
Here’s a video of the problem and pics of the line trace system/Inventory (can’t be more classic) and levelBP, my subs levels BPs are empty as well as my master interactable BP.
https://youtu.be/7F-i_wZPAtc I’d recommand to play it half speed 
Line Trace System
Inventory
LevelBP
