Need pro help: 25p to 24p pitch shift -> Elastique is phasing! Zynaptic instead?

So the film was shot in 25p, now after everything is finished, the production company told me they actually do need a 24p version. So it's pitch shifting time!

I used X-Form back in the days, but dont have that plugin in my studio.

I now have my hands on Elastique V2 or AAX. Im still in demo mode.

I thought I could save some money using just V2, as the pitch shift algorithm under the hood shall be the same.

Here is what I noticed with Elastique: when I render it via AudioSuite on two completely identical clips, they won't null doing a null test. In fact, they start phasing badly when played together, like there is some randomness within the algorithm. Same with V2 and AAX (same with V2 as inserts on two tracks with identical clips on identical positions on the time line).

Problem is, when I use Elastique on the DME stems, nasty phasing appears here and there, when summing the stems. That's because there are some sounds on the Dx stem from production sound, that were also processed and used on the Fx track. Same is for the Fx and Mx stem: some Fx sounds also play a musically part in the Mx stem and are on both, the Fx stem and as a slightly processed derivate on the mx stem. This style of distributing the sounds to their stems isn't ideal, but they did not know the complications that would cause.

Whenever these specific parts come together, the phase correlation is disturbed by Elastique and the stem sum sounds horrible. And that's just what I figured out by now. Going through the whole thing might reveal some other problems caused by the pitch shifting.

Zplane did not get back at me about this yet. Their first answer was, that this shouldn't be the case and I should in fact hear proper cancelation doing a null test. Am I overseeing something?

I then tried RX Advanced, it uses RADIUS (same as OG X-Form), but gave me the same problems, similar phasing, even though the settings where identical.

I then tried Waves SoundShifter: no phasing here (just the typical nasty artefacts). So is it really depending on the algo being used?

Would Time Factory II by Zynaptic give me better results?

How do you guys handle this more than unfavourable "workflow"?

Every tip is highly appreciated.

In the end I want to use different settings for dialogue, for music and for effects, so these different settings could phase. So I would have to go through the whole movie, listening carefully to where the stems add up badly, and then apply coherent settings for the pitch shift algo, or even a different plugin, so the stems will add up without distortion? (I experimented with the "phase coherence" parameter in RX but that did not do the trick yet)

Pitch shift time now becomes unpaid overtime.