I am currently correcting assignments (pass/fail) for a Bachelor's course in which I am a TA. Students write some code and then discuss their results and approach in a report (in groups of two). My task is to "review a report and provide feedback for students how to improve their report" then they do a supplementation and pass.
The task/content is the same for all students so I will naturally encounter similar results.
While writing feedback I've noticed that I was pointing out exactly the same mistakes in two reports (including the same typos in equations). Upon closer inspection I realized both groups provide the same results and (more importantly) fail to provide results in the same area, i.e. the program should be run with different parameters, both groups only run one (and the same) set of parameters.
Both reports follow the same structure with small permutations, e.g. renaming sections or rephrasing of sentences and make the same "meta" mistakes like discussing their results in the conclusion.
However, looking at the code it looks like two different implementations (i.e. they seem to be using their respective code).
My initial response was to escalate this to the professor in charge and let him deal with it, but then I realized that I might be too pedantic, which I sometimes am. (My impression is that any of the other TAs would just shrug it off as "odd", but not do anything further.)
One of the groups has already caused trouble for another reason, so I don't want to "accidentally" escalate the overall situation.
I guess my question is how to apply the ethical guidelines of "propper scientific conduct" in this gray(ish) area, given that it is some "unimportant" assignment (of many) for a Bachelor's degree course. Should the needle tip towards "turn a blind eye" or towards "no exceptions".