When i first place a wall, i am able to phase through it even if it is a solid - non broken wall, this is only client side though as even though i can see myself going right through the wall i can't do anything without going around the wall. Secondly, if a wall is broken i can freely pass through it at first, but upon unloading and reloading the area (getting far away and going back or relogging) the walls become solid for my character, meaning i can't pass through them even if they are broken, but everything else is able to go right through.
I tested this on a world without mods and the issues are still there, this bug is bad because you can't go through broken walls (which are sometimes used as decoration) and you have to run far away and back if you wanna collide with walls (could be for aligning statues or other objects)
Other people on the server also have the same issue, so it's not only me that's suffering from this bug.
While going through solid walls is client side, not being able to walk through broken walls seems to be either server side or just client side not being able to traverse walls, also if you go through a square of broken walls the physics engine will go haywire and your character will wildly spazz out and start pinballing through the walls until it finds its way out of the wall.
I've noticed this glitchiness happening on the Hook, Line, And Inker update, though it might have been present before then.
Place a wall and try to walk through it, place a wall, break it, move through it, relog, witness as you aren't able to go through the wall (works better with multiple walls, or a solid, broken-wall square)