I know it will under certain circumstances where the path is broken or incomplete and a 403 is returned, but it doesn't seem like you're getting that here. It would be hard to say ...
You'd normally get a 414 if the request URI were too large (over 8k), so if you're getting a 200 and then the bad line, then it would not be that specifically.
This error is coming from an APEX trigger in SFDC, so there's not much we could tell you from the Marketo side. I'd take the error and the records where it occurred to your SFDC ad...
Strictly speaking, option 1 should be (minutely) faster if the value is the same, option two a bit slower if the value ends up changed. Both will query the value to see if a change...