Blocks randomly appearing/disappearing

I'm running a bukkit server with the latest version of minecraft.
The server runs on my laptop with 6gb of ram, and no other programs running. Ever.

I've been noticing that blocks seem to randomly vanish from the world. It's not enderman or creepers since mobgriefing is false. Sometimes it's stone brick, a chest, polished stones, but random blocks will just disappear. It's getting VERY frustrating.

Also, random blocks spawn in places. Usually in water, underwater. Stone, or cobblestone. And often in a straight line, which is weird.
X = block _ = space
X_____X_____X_____X_____X

That's how stone appears in the water sometimes. I know it's not another person on the server, because I know everyone who's logged on and off, and not only would they do this, but it happens in too odd of places for them to be responsible.

Only mods I run are: MCmmo, deathbukkit, stargate, Dynmap, and Chest lock

 

Hmm what version are you running? Also ram on your pc plays little role, the matter is java's allocated ram

 

I'm running Bukkit 1.8.1, and I have 6 gigs of ram allocated to the server. No other programs run on that laptop. It just sits in the corner, running that.

 

Moved to Bukkit Alternates.

 

We had the sparse blocks over water, along a line, but also rectangular around the player, seemingly over not yet rendered water chunks appearing in the distance, those blocks were not "real" and disappeared with chunks rendered.

 

These blocks are most definitely real, and have to be destroyed. The disappearing blocks are getting annoying too. Especially when it's a piece of railway that vanishes, or a torch, a sign, or just some laid redstone.