Usually when the blueprint deployer places a blueprint, it also automatically marks natural elements (trees, rocks, cliffs) for deconstruction as well. However, I've encountered a problem where this sometimes doesn't happen when just the edge of the cliff is overlapping an element. This causes my construction robots to get stuck trying to place an element on top of a cliff that is never destroyed (see linked images below). I could fix this myself using a deconstruction planner, but since cliffs are usually deconstructed automatically, I assume this is a bug.

Images:
https://drive.google.com/file/d/1vwI7CEA0YV7q9mjv5i7fNybHW6I-ldwD/view?usp=sharing
https://drive.google.com/file/d/1z5Kdx8s0nt41XNgF0F_cz790ppGWi8eo/view?usp=sharing

I did a quick test to see if this was just a problem with the force blueprint placing in Factorio in general. I found an example where my machine got stuck and removed the unnecessary things around it (https://drive.google.com/file/d/1-j-AOzALoyKc2mKej-HpsDIoApcNkSpS/view?usp=sharing). Then I removed the ghosts and forced placed the chests manually. This correctly marked the cliff for deconstruction (https://drive.google.com/file/d/1cRTm-DQmWCm9MJ3OBe0Kpr_mfbGLeAGv/view?usp=sharing), suggesting that the problem comes from how the blueprint deployer places the blueprint.

Taking a closer look, it seems that the problem only occurs when I don't look at my machine. It got stuck again, so I tried letting the blueprint deployer deploy again. This time, it successfully marked the cliff for deconstruction, so it's not a problem with the blueprint deployer. Perhaps the game is skimping on precise calculations when I'm not looking directly, leading to mistakes?

I found the actual cause of my problem. I backed up to a previous save and watched as my machine get stuck on a cliff (video: https://drive.google.com/file/d/1gIOI_9BTcMsmoWeGqPoUgAfSpzu4pmV4/view?usp=sharing). What happened is that the cliff is initially only overlapping the machine, and that part is correctly deconstructed. However, when that part is destroyed, the hitbox of a previous cliff changes and starts to overlap with a ghost, which causes the robots to get stuck. This makes it seem that this isn't a recursive blueprint problem, and instead a base Factorio problem.

I would guess that it is related to this -> https://forums.factorio.com/viewtopic.php?f=48&t=66400