Placement collision with the ground

I have had a mod running for months that I had removed placement collision from copies of the core game parts. Everything was working great. Recently (about 2 months ago), something changed and ground collision has become a problem during placement. Places where I used to be able to put a part no longer will accept the same part. I have tested and found that if I go into ghost mode and go under the ground surface I can place the part in the spot that I wanted. Can anyone help with this? Is there another way to avoid placement collision that will work better? Something with blueprint? Thanks!