I thought Flows were nice and easy to work with, but when anything goes wrong in the middle of a flow - especially inside a Do Until loop - good luck with figuring it out. Not only does the flow just stop and report 'Failed', but you have to dig to find an error message that isn't helpful at all. For example, last night I had a flow that works fine and had run the step setting a boolean variable HasMore many times, it failed with the error 'Invalid Template. Unable to process template language expressions in action 'set_HasMore' inputs at line '1' and column '2771': 'The template language function 'variables' must have only one parameter.'.
This message is not helpful at all and there is no reason it should fail on the 275th pass.
It would be nice if it gave more insight into the exception and even better if we could handle the exception, log it and continue to report what the Flow accomplished up until the error.