From the MSDN help:
"_SECURE_SCL defines whether Checked Iterators are enabled. If defined as 1, unsafe iterator use causes a runtime error. If defined as 0, checked iterators are disabled. The exact behaviour of the runtime error depends on the value of _SECURE_SCL_THROWS. The default value for _SECURE_SCL is 1, meaning checked iterators are enabled by default."
The Liquid C++ Runtimes are built with the default where _SECURE_SCL = 1, setting this value to 0 will cause the code to crash in release mode as the values must be consistent across the exe and all dlls.
The only way to fix this issue is to set _SECURE_SCL = 1 or purchasing the Liquid Runtime C++ Source Code and building the Liquid Runtime library yourself.