The Town's protection system is not preventing the blocks from being destroyed by explosion.
The creepers explode and vanilla blocks break (modded blocks do not destroy).
Also when you "hang" a Citizen with a lead, he will "explode" and break blocks as well.

Apparently explosions are not prevented and blocks are being destroyed within Town's protected area.

This definitely needs a log as we are preventing explosions pretty throughout.

"Unverified"?
Do you need a server log? A client log? Just login to the Official server and BOOM! either a creeper of TNT player placed.
Do you need more information from player side?

Yes i tried this myself, i could not reproduce it. Granted i tried this on client only. But i had no problems.
I will move it to verified as you say you can produce it on the official server then.

Yes, just login to the official server and you'll see. Not sure if it's a server side config or issue with the server side mod or spongeforge. All users complaining.

Also happened on my server (also sponge) two times today with creepers with the last release minecolonies-universal-1.10.2-0.6.299.
Never seen before with previous minecolonies releases (but same sponge release)
I didn't catch any log for that

@Kostronor So.. since it wasn't an issue before... you think it might be a matter of a simple config that changed and can be reverted?

A sponge issue have been fixed here : SpongePowered/SpongeForge#1364
Hopefully this will do the trick, I will test as soon as it will be released

should be fixed