the community discussed some facts about chests in this thread:
Thread
Dear community,
first of all, english is not my native language so excuse the mistakes in the following text.
Today, someone in my alliance chat stated, that he had zero chest spawns while vanquishing Maishang Hills. I was answering in alliance chat that this is just impossbile. A map of this size has to have chests. After some minutes of discussion we both were still defending our statements. I am sure, maps of this size have chests. Especially Maishang Hills has some nice corners with pop-up…
Jodel_GW
March 25, 2020 at 10:29 AM
I doubt that chests will spawn more often along your path when not having keys/lockpicks with you. As far as we know, spawn position is totally random over a map with some rules, for example the maximum number of chests per map, distance of chests to each other, etc.
It is hard to test this because you need lots of runs with and without keys and your test set should be always the same (which is hard as we still don't know all factors that can influence chest spawns, chest drops, etc).
I think you are good to go with "it is just random and maybe you just realize the situations without keys".
But the community is always happy to get proven wrong.