I've searched the caves quite a few times and searched the lab ruins multiple times and I've only ever found 2 ichor containers, are there no more currently in the game or am i doing something wrong?
Ichor containers should respawn about once a month and there are like 4 different spots they can spawn at. Once a container spawns, it doesn't move or spawn again untill you pick it up.
So in short, if you wait a month and you can't find a container, try waiting one more week. If there is still no container then you are most likely missing a spot where it can spawn.