Problem with

I have this problem on different workstations (Apple StudioUltra - AMD Threadripper), so I think it's a structural problem of fusion.
In any case, the characteristics of the PC with which I write and I captured the screenshots are as follows:
CPU AMD Ryzen9 7950X3D;
Motherboard Asus ProArt X670E-Creator ATX 128GB;
RAM 128GB GSkill Trident Z5 Neo (Mod.ExpoII);
Video Card ASUS NVIDIA GeForce RTX 4090 24 GB GDDR6X;
SSD Samsung 990PRO (4 on board to manage from different disk OS - working clips - chace disk - broll)
Windows 11 Pro 22H2 OS Build 22621.1992

- Before describing the problem, I explain the most inexplicable thing: once my node editor structure in Fusion is finished, I have a correct representation of the work (as it should be) on the Fusion MediaOut, but when I go back to the Edit Page the result instead is different and are being generated - error displayed.

- this error persists despite having done: erasing the chace, reloading the DRA, exporting video in different formats, installed up to the latest version of DR 18.6

- I've never considered the option of using saver - loader nodes, because I work in BRAW and RED RAW, so I MUST have to keep the advantages of RAW up to the Color. I purposely bought an Ursa 12K to have maximum compatibility in DaVinci...

- The problem persists even with only BRAW jobs with Ursa 12K and BMPC 6Kpro.
- Same problem regardless if I use BRAW or ProRes444 from Sony camera.

WORKING:
the problem generally occurs whenever I have a clip where a subject moves over a background and I need to retouch the background.
Obviously if the subject moves I must fragment the intervention on the background to use the parts not occluded at that moment, therefore I have to use a Time Strecher node to freeze the frame, so I correct on an area which will then be merged with another area with the same technique. To carry out this correction we will therefore mainly use the nodes of Time Strecher - Paint - Matte Control - Merge.
Then, now I must isolate the subject using a mask (Polyline or Bspline) which acts on a Matte Control (inverted Garbage input).
Finally the moving subject will go to the Foregroung of a merge node where the Background is the result of the background correction performed by merging the different areas managed by the TimeStrecher.
My background interventions can be simple uses of paint only as a PNG application, etc

THE PROBLEM:
When I finished the job I check the mediaout and it's all correct, everything works perfectly, but when I go back to the EditPage it's a completely different result with the subject swinging some frames forward and some backwards like ping-pong and then jumping at the end of the frame.

MY THING:
My thought is that there is an incompatibility between Fusion and Da Vinci Resolve, a non-integration. The Time Strecher node works fine in Fusion, but handles time data incompatible for the Edit Page and DaVinci Resolve, which fails to interpret this data correctly.
I've already had other types of problems of this type in the past (which I won't list now), but this is the most serious problem because this actions is the basis of all my compositing works.

- I've never considered the option of using saver - loader nodes, because I work in BRAW and RED RAW, so I MUST have to keep the advantages of RAW up to the Color. I purposely bought an Ursa 12K to have maximum compatibility in DaVinci...

I don’t have a solution for your actual problem but this above needs a comment. Any ”rawness” of any format is lost when that format hits the decoder. Even before you can see it, it isn’t raw anymore, so there is nothing ”raw” to keep. What you can keep is full fidelity of the decoded data and this can be accomplished using suitable intermediate file format. For linear data, exr sequences, for logarithmically encoded data, prores or DNx 4444 variants are good enough.

- I've never considered the option of using saver - loader nodes, because I work in BRAW and RED RAW, so I MUST have to keep the advantages of RAW up to the Color. I purposely bought an Ursa 12K to have maximum compatibility in DaVinci...

I don’t have a solution for your actual problem but this above needs a comment. Any ”rawness” of any format is lost when that format hits the decoder. Even before you can see it, it isn’t raw anymore, so there is nothing ”raw” to keep. What you can keep is full fidelity of the decoded data and this can be accomplished using suitable intermediate file format. For linear data, exr sequences, for logarithmically encoded data, prores or DNx 4444 variants are good enough.

Even if I convert all BRAW and REDRAW to DNx 444, Fusion generates the same problem. The only way out that came to mind is to generate various levels of BG and FG output and compositing in Edit, Render in Place and Color Page, but I find it really frustrating and non-productive.

That's because Fusion integration into Resolve is a huge mess.

You have a couple of options.
The first is to use a Saver/Loader set up and set it to render EXRs. Add a Saver/Loader right before your Media Out. They're heavy but will have all the detail you need. You can set the bit depth ahead of time so you aren't rendering 32bit EXRs if you only need 16bits.

The second is to manage your caches. Add a Boolean before your MediaOut and use it as a caching node. Right Click and select Cache to Disk. In the dialog, select the folder and put your cache in a place of your choosing. Caches save as Braw files so it will be in the format you were trying for.

In both these cases, you're timeline should be rock solid. Do a Render in Place and hopefully have a beer.

Hey,

The OP is long, but I almost read it all ...

I see 4 options for you, but 3 have already been written here.

1/ you don't want to render cache and I understand it's not a real solution. However, as fo the magic mask cache issue, it's still a solid option ;
2/ The 1st option coming in my mind is what Ben wrote above : a saver "bakes" everything and you get back exactly what you comped before in the end ;
3/ The cache fix : I wouldn't use a boolean but that's fine indeed. Anyway handle your cache in both Fu and the Edit page before trying any monitoring ;
4/ I think this one may really fit your needs : I assume you're on the Studio version ? If yes, consider the VFX Connect way instead of the Fusion tab... It would properly refresh in the edit page, and you could rely on everything Fusion standalone can do for you. This would wipe out any issue related to the relationship between Resolve's tabs : you do your work > when finished you render in Fusion > back in the Edit you properly find it all back