Just wanted to drop a note here because I don't think this is fixable but I noticed a curious interaction with AAI Programmable Vehicles of all things.
AAI Programmable Vehicles adds in an "exclusion zone" around enemies like biter nests. While by itself this does nothing, when combined with this mod, it does present a curious case as follows:
Capturing a biter nest turns it friendly and thus removes the exclusion zone, meaning turrets can then be built around it.
However, once the biter nest starves and becomes wild, the AAI exclusion zone will kick in. Our wall of turrets then does turret things and kills the now-spawning biters.
The baby turret grows up and tries to upgrade its quality, but however because the exclusion zone is now there the baby turret has a crisis of existence and vanishes.
Like I said, I don't think this is fixable but I did want to leave this here for anyone else who might come by and wonder where their wall of baby-sitter turrets went.