Maybe it's just on my machine but I believe I found a compatibility bug between Deferred and ReStock.
Whenever I have both installed at the same time, the main part (metallic structure) of the launch stability enhancers appear invisible in the VAB and HAV but not while I actually launch my vessels. If I have one of these two mods removed from the game, I'm able to see them as normal.
I also took this screenshot with only ReStock and Deferred installed to show the issue:

Here's the log too (with more mods installed but the issue still happening):
KSP.log