Simple Lua code:
print(string.format("Test%d", "NotNumber"))
In Lua 5.3.3 console:
bad argument #2 to 'format' (number expected, got string)

However, in 1.80pr1, it results with:
java.lang.ArrayIndexOutOfBoundsException in red.

That shouldn't happen as I doubt any recursion is happening in string.format, as I've seen that is a reason for it to happen in another (fixed) issue.

Please fix up the LuaJ string.format to soft error rather than throw an exception.