ACES Output Transform

I have a project that I'm coloring using ACES cct Version 1.03 in Resolve v14.3 and I'm running into some bumps in the road. Grading Alexa footage, using Alexa IDT and REC709 ACES Output Device Transform.

I graded the first episode of this documentary style project using ACES and the client liked it, however these new episodes I'm getting have a lot of media supplied by the subjects of these interviews. I can turn off the ACES input transform, but the problem I'm running into is the output transform appears to be doing something to these images. These were originally jpegs, but they've been baked into a video that has been cut up, so I'm not working with raw material.

The Alexa footage looks great, but on these stills and computer video captures the image color is shifting dramatically. I can turn off the input transform but cannot figure out how to turn off the output transform on these clips, so I don't see a way to completely clear it of all transforms, or wrangle it in somehow, and grading it to look normal is going to be time consuming and the client may not be satisfied. If I turn off the REC709 output transform in the project settings I'd still need to find a way to get it back on to the Alexa clips where it's very useful.

One other problem is that when I turn on broadcast safe the image just goes crazy and on the scopes the luminance won't reach 640. Probably it's not necessary to have broadcast safe on with ACES since its got the Rec709 ODT , I don't really know, I haven't run into this before.

I'm sure I'm doing something wrong here but I don't know what.

try a 709 IDT for the archival and misc mystery footage
leave the ODT matching your monitor -or- delierable

Not sure if this going to be practical but as a suggestion you can actually run ACES using the Color Space Trasnform OFX under YRGB mode. If you put those transforms in a group for the Alexa clips while excluding the backed clips you may get what you want.

But, I would await advice from BlackMagic though, groups I find have often performance issues.
Hopefully some Blackmagic expert can comment on your problem.

Thanks guys, Dermot's idea is working for me. I've done a few ACES projects now but I'm not an expert and this appears to be what I've been looking for to just clear off the appearance of any transforms, even though technically I'm still using them.