Crash during rendering: irradiance map thread

When rendering multiple frames, the second frame consistently keeps crashing 3dsMax as soon as it reaches irradiance map calculation. When rendering a single frame it renders ok.

[2015/Sep/1|12:53:15] Light cache contains 944344 samples.
[2015/Sep/1|12:53:15] Light cache samples collected; compiling lookup tree.
[2015/Sep/1|12:53:15] Light cache takes 143,3 MB.
[2015/Sep/1|12:53:15] Prefiltering light cache.
[2015/Sep/1|12:53:15] Average rays per light cache sample: 4,45 (min 1, max 4263)
[2015/Sep/1|12:53:15] 1 interpolation maps registered
[2015/Sep/1|12:53:15] Rendering interpolation maps with minRate=-3 and maxRate=-1
[2015/Sep/1|12:53:15] Setting up 12 thread(s)
[2015/Sep/1|12:53:34] error: UNHANDLED EXCEPTION: Irradiance map thread
Last marker is at ./src/globillummap.cpp, line 1932: GlobalIllumMap::buildLightMap() {5}

Vray 3.20.02 on Max 2015 x64 / Win7 x64
Exactly the same happens with Vray 3.20.03 on Max 2016 x64 / Win7 x64

Plugins used: Forest Pro, Railclone Pro, Multitexture, Bercontiles/noise

Is there a fix for this? Currently the workaround is rendering one frame at a time…

Found out it was a Railclone object, a temporary fix has been made available by Itoo soft: Log in