Hi @Adrix,
The main requirement here is finding a way to identify the “groupings”. After that, it becomes a relatively trivial exercise to then count the members of each group, and find the maximum. The groupings in this case are identified by change of value in the Results column.
One possible solution borrows (steals! 
) from the solution provided by @HansS from a “similar” scenario
which I have adapted to your problem.
A second possible solution uses a component that can handle this kind of requirement generically:
The attached workflow provides both, and they both return the following:
Counting the max of consecutive days in error - with or without component.knwf (45.8 KB)
Component is here: