The way I see it. Thymolated syrup is fed as an Autumn feed for overwintering.
It will sit in the brood combs as a store.
Next season, the bees will bring nectar in and store it, initially in the brood chamber.
Some of that stores will be moved up into a super, if you add one, and maybe quite a bit if bruising the cappings to get them to shift it.
Whether it is thymolated stuff that gets moved up or not, is not the issue. Hopefully it will all be eaten before a chance to move it into a super.
But eventually, stores will go where that stuff was, in the same cells, absorb the smell and some of it, will get moved up into the honey supers. Either by the bees own volition or by working the brood frames.
You can try and keep it out directly from the supers. With maybe some degree of success.
But for me it's more a case of future stores being placed in the same cells and absorbing that lingering smell, where it once was.
And bees do move stores around.
I'd rather stay away from it for that reason.