I've looked around and cannot find any reason for this, and cannot find any maximum length for ladders. So here is the situation.

I am mining ores. I start with pretty big opening and then put down some wooden blocks, and attach the first ladder to it, as I continue to go down further and further I add more ladders so that I can climb out of the hole.

At some point, usually like 7 or 8 ladders down, adding another ladder causes all the ladders except for the one connected to the wooden block, to fall off and crash to the ground. I then end up having to dig a diagonal ramp up and out of the hole.

I've been using wooden ladders, I don't know if using metal ladders would make a difference. The ladder is not obstructed in any way. It goes straight down from the center of the hole that is probably 4 blocks or maybe even 5 across.

Any help would be appreciated. I'm on 18.1.