I have been searching for while for a good resource, where the circular dependency is well explained, unfortunately nothing good found. Therefore I tried to understand exactly which kind of circular dependency I should avoid. The problem is I found some resources which explain in contradictory manners. Could someone explain exactly please which types of circular dependency we should avoid (and why)?

Taking these relationship as an example:

Source

This relationship is mentioned here to be bad (I do not understand why).

However, the same relationship is mentioned to be not a problem (and is described as NOT circular) here:

Models <--------------------------- SuperSets    ^                                    ^    |                                    |    |                                    | Tasks  <---------------------------- Sets 

Source

Another example is this:

Source

I also do not understand why is this a circular relationship?

All of the previous relationships seem to me not curcular (the arrows direction is not going back to the same point). I think there is something wrong in my understanding for circular dependency term. Could some one explain that for me please in general, and particularly also maybe on the previous examples?