From a quick check on FUT.gg the deep lying playmaker and Rodri evos are different evo types, with the former being a type 1 and the latter being a type 3. So I don’t understand why there would be a problem if you finish the first one and then evo’d a second Ndidi card as they are two different card types however I’ve never tried it myself, so maybe I’m missing what the issue is?
Edit, just looked it up and it appears you are right. That’s a bit crap. However, it appears quick selling the old evo gets around it. Some one tried to recover the old evo after they’d completed the new card and apparently this generated a duplicate version of the new evo