It's only really a minor issue. Most games are not affected by it. It causes maybe something like +/- 2px difference. Given that dt has small random variations that can alter the game as well, you generally should design your game with enough tolerance anyway, so that this kind of offset does not meaningfully impact the gameplay. With Construct 2 being in widespread use for ~6 years, it has affected few games, and for the most part accuracy to within a few px is just fine.
It was also a pretty complex change in the end, we basically ended up rewriting all the movement math used in behaviors, and it caused a few extra bugs while we got that right (like this and this, and would not be surprised if there are more since we only just fixed that second one). We're focusing on C3 for all new improvements, and that kind of maintenance overhead when making a new improvement is the kind of thing we only have the resources to put in to C3 going forward.