Compiling Issue - can't find cause of the leak

I keep getting a leak message can't find the error - can anyone help? ran BSP and fast vis only

I've even enclosed the entire map in a box - sealing it and I still get leak message - here's the log:


** Executing...
** Command: "c:\steam\steamapps\kill_the_bug\sourcesdk\bin\orangebox\bin\vbsp.exe"
** Parameters: -game "c:\steam\steamapps\kill_the_bug\team fortress 2\tf" "E:\C drive backup\Desktop\maps\gold_heist_Canyon_B1.vmf"

Valve Software - vbsp.exe (Jul 7 2010)
4 threads
materialPath: c:\steam\steamapps\kill_the_bug\team fortress 2\tf\materials
Loading E:\C drive backup\Desktop\maps\gold_heist_Canyon_B1.vmf
Patching WVT material: maps/gold_heist_canyon_b1/nature/blendgroundtograss001_wvt_patch
Patching WVT material: maps/gold_heist_canyon_b1/brick/blendcobbletocobblesnow001_wvt_patch
fixing up env_cubemap materials on brush sides...
ProcessBlock_Thread: 0...1...2...3...4...5...6...7...8...9...10 (1)
**** leaked ****
Processing areas...done (0)
Building Faces...done (0)
FixTjuncs...
PruneNodes...
WriteBSP...
NODRAW on terrain surface!
NODRAW on terrain surface!
NODRAW on terrain surface!
NODRAW on terrain surface!
NODRAW on terrain surface!
NODRAW on terrain surface!
NODRAW on terrain surface!
NODRAW on terrain surface!
NODRAW on terrain surface!
done (0)
Creating default LDR cubemaps for env_cubemap using skybox materials:
skybox/sky_day01_01*.vmt
! Run buildcubemaps in the engine to get the correct cube maps.
Creating default HDR cubemaps for env_cubemap using skybox materials:
skybox/sky_day01_01*.vmt
! Run buildcubemaps in the engine to get the correct cube maps.
Finding displacement neighbors...
Found a displacement edge abutting multiple other edges.
Warning: invalid neighbor connection on displacement near (2080.00 1203.00 301.00)
Warning: invalid neighbor connection on displacement near (2080.00 1183.00 -192.00)
Warning: invalid neighbor connection on displacement near (2128.00 976.00 307.40)
Warning: invalid neighbor connection on displacement near (2080.00 888.00 321.00)
Warning: invalid neighbor connection on displacement near (2080.00 933.56 -192.00)
Warning: invalid neighbor connection on displacement near (2640.00 1309.00 381.00)
Warning: invalid neighbor connection on displacement near (2640.00 1354.56 -132.00)
Warning: invalid neighbor connection on displacement near (2688.00 1349.00 359.68)
Warning: invalid neighbor connection on displacement near (2640.00 1624.00 361.00)
Warning: invalid neighbor connection on displacement near (2640.00 1604.00 -132.00)
Warning: invalid neighbor connection on displacement near (2128.00 928.00 299.68)
Warning: invalid neighbor connection on displacement near (2688.00 1397.00 367.40)
Finding lightmap sample positions...
Displacement Alpha : 0...1...2...3...4...5...6...7...8...9...10
Building Physics collision data...
done (2) (474967 bytes)
Placing detail props : 0...1...2...3...4...5...6...7...8...9...10
Compacting texture/material tables...
Reduced 3058 texinfos to 1039
Reduced 25 texdatas to 23 (664 bytes to 544)
Writing E:\C drive backup\Desktop\maps\gold_heist_Canyon_B1.bsp
5 seconds elapsed

** Executing...
** Command: Copy File
** Parameters: "E:\C drive backup\Desktop\maps\gold_heist_Canyon_B1.bsp" "c:\steam\steamapps\kill_the_bug\team fortress 2\tf\maps\gold_heist_Canyon_B1.bsp"

There was no point file file generated but just after I posted I got an idea.

I deleted all the cube maps then ran it - this time it identified a brush that had something weird with it - I deleted it - ran again and no issues.

Got to say this was the weirdest one I've ever seen.