Do the dumpsters look slightly open? I've noticed some do not seem to be shut properly and I can't do anything with those, it seems to be more on placed lots from the bin than ones already in world so far though.
The junkyard is an example, when I first started my immortal dynasty they were fine, all closed and I could dumpster dive, but I've noticed a few times since when I've placed it for a challenge they are slightly open and I can't use them. I did some testing by bulldozing and replacing the lot and still open, selling and replacing the dumpsters and still open, not sure what causes them to do that but can't seem to fix it so far.