Personally I have exactly the same problem. When I try to make either a grating or a perforated sheet metal railing, the phenomenon also occurs. I validate the function, then I do another function (any function) and there the repetition gets wrong and when the comes back on it, the parameters have changed.
Never found the cause, I thought it was because of the number of occurrences, because it generated a lot of material removals, but in your case, the number is not high.
Can you post your part, I'll look because I have the 2018 version?
And may the force be with me ;-) is not Obiwan
Waiting for what I see:
1°) it's that apparently your area intended for repetition is smaller than the lattice structure. Normally, everything should be iclus in the area and not partially straddling in my opinion. You need to make a second sketch for your guide line of your repetition or in the same sketch that defines your surface (but put your guide line as a "construction line" it should work)
2°) you don't say delete the occurrences not to be repeated (cf occurrence to omit).
3°) we should see the incidence of the following functions, in this case [Body move, copy] and then then [combine]