Hi Craig, thanks for the reply.
Here's my code that breaks.
x="1234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456"

That's 256 characters in the definition of a memory variable.
Not sure why this is breaking.