Hope the exams and study is going well!
At T:12.7s when contact occurs, both boats are tacking and are both therefore subject to R13.
13 WHILE TACKING
After a boat passes head to wind, she shall keep clear of other boats
until she is on a close-hauled course. During that time rules 10, 11
and 12 do not apply. If two boats are subject to this rule at the same
time, the one on the other’s port side or the one astern shall keep
Because we are both subject to R13 at the same time (as seen in the screen shot above where we both have not reached CHC yet) the one on the other's port side shall keep clear.
So as stated in the rule, you being on my port side means you're at fault of breaking R13...the system never picks up R13 in these situations.
Thanks and Fair Sailing!