Block issue - spontaneous duplication of objects within block after multiple updates - (Applies to 2017 as well)

[Cypress_Steven]

Let's say I create a block for a building with just a few layers for the building outline, building overhang, and doors. There are no over-lapping objects.

If I close and save the block, and then later on I adjust the block, and continue to do so maybe a few times over the course of a week...at some point I will go in and find that there are duplicates of the block elements (1-7 I think I've seen before). But yet I have not copied these elements in place.

Attached is the .dwg with an early version of a block that is fine and a later version that decided to procreate objects itself.

Notes that may be useful:
-Not a dynamic block
-I often purge and audit all my drawings, including ones that have blocks in which this error occurs
-I'm using 2018 LT currently, but i'm pretty sure I first noticed this problem when we were using 2017 LT.

Any help would be appreciated.
Thanks!