This is also happening on fences. If the fence is above the room below, the column goes to the top of the fence rather than the top of the room...
Ran into this issue as well after the recent patch! However what I did to solve this problem was to grab the offending column, place it at a section of the wall that is of the right height. This would resize the column down to the correct size and then I grab it again to place it at its intended placement, where it will stay with the correct length.
I have a related issue, one of my houses has columns in the first floor, and they are poking through the second floor, this was never an issue before. I also noticed that if you change the height of the wall and then change it back to the regular height it gets fixed temporarily, but after you reload the save, the bug comes back.
A simple fix I've found is to go to build mode and change the wall height from what it is to any other wall height, then to undo it, the columns remain fixed and any items you lose return as if they never disappeared, you have to do this for each and every level...and I'm pretty sure for this fix we'll have to do it each time we load up until they fix it in the next patch...but I think this is a pretty simple work around that you don't have to pay anything for and don't have to loose anything but a few minuets for ^^. Even if it is annoying O^O
September 2019 - last edited September 2019
Product: The Sims 4
Which language are you playing the game in? English
How often does the bug occur? Every time (100%)
What is your current game version number? 18.104.22.1680
What expansions, game packs, and stuff packs do you have installed? All as of 6th September 2019
Steps: How can we find the bug ourselves? Place column on bottom floor. Go to floor above. Place flooring above. See shadow glitch.
What happens when the bug occurs? A shadow appears on floor above column. It’s black and shifts and glitches as the game camera moves around.
What do you expect to see? No shadows on floors above columns
Have you installed any customization with the game, e.g. Custom Content or Mods? Not now. I've removed them.
Did this issue appear after a specific patch or change you made to your system? Yes
Please describe the patch or change you made. After September 2019 patch
This is a super annoying bug that has started the first time I’ve opened my game since the September update.
its happening with all the columns on my legacy family lot and all columns on other lots (I went and checked).
I’ve tried deleting all the columns and replacing them. I’ve tried saving the lot and placing it again. I’ve tried restarting my game. I’ve also take out all mods (I only had mccc and an ultrasound mod). Nothing has worked.
I have no mods and am having this issue after the patch. Also, some of my houses' columns are no longer adjusting for height.
There are too many models affected by this bug for a work around to be acceptable. At least all models that have short columns are affected and may be the other models with other size columns as well. It is too much work for those that have uploaded many models to go through them all and fix each one of them. It is also unreasonable to expect those that have downloaded models from the library or planned to do so to fix them; a fix is necessary.