I just tested both these skills, and it works fine.
I also tried something else just in case: I tried adding both conditions to the same talisman. The editor indeed overwrote the first with the second (as of course - you can't "solve with only shimmiers" and "solve with only platformers" at the same time, except by finding a solution that uses no skills at all).
Can you double-check you are indeed using V1.19 of the editor (Help -> About), and if so, can you describe some steps that consistently produce this issue?