I'm running SecurityCraft v1.9.6, on Forge 1.12.2.

I've noticed that applying a Disguise Module to a Sentry prevents any interaction with the sentry. The sentry can't be sneak-clicked, its firing mode can't be changed, no other modules can be added, and the block the sentry disguises in can't be broken by mining, even in Creative Mode. The sentry still functions as normal.

I've tested and found that using /setblock to set the sentry block to air re-enables the interaction, and using TNT also destroys the sentry, regardless of which block it's disguising as.