So I figured the problem must've been solved with the new Acrobat XI
What version of AcrobatPro had you been using and what is your Output Preview setting?. It sounds like your RGB blue is out of gamut and you are viewing a CMYK output preview.
Here's and out-of-gamut RGB image in ID and exported as PDF/X-4 in Acrobat. Top with a CMYK simulation profile and bottom my ID document RGB simulation profile.
I totally get what you're saying about the lighter blue color being out of gamut... but those blue tones don't go away when I turn on Proof Colors (CMYK) in InDesign. They just wash out... the deep blue/blacks aren't as rich etc.
I was using Acrobat X Pro 10.1.7. I then downloaded the trial for XI. That's when the weirdness happened. The new PDF came up correct in XI but then some weird “trusted certificates” message appeared and the PDF color reverted after I clicked ok.
NOW... I just ran the update to XI 11.0.03 and the PDF is correct! If I open it in X it's wrong. So the real question is can Adobe provide a patch to fix the problem in X because this $200 for a new version is bunch of BS!
when I turn on Proof Colors (CMYK) in InDesign.
Does the profile you are using in ID's Proof Setup match the Simulation Profile you are setting in Acrobat?
Try turning off Proof Colors and turning on Separation or Overprint Preview, then in Acrobat use your ID Document's CMYK profile as the Simulation—use the assigned profile (edit>Assign Profiles), not the Color Setting's Working CMYK profile. When you export use the PDF/X-4 preset.
I don't think there's an issue there... The profiles are in sync in ID and BOTH versions Acrobat Pro... North America General Purpose 2 (both are using U.S. Web Coated (SWOP) v2 for CMYK and sRGB for RGB).
Whatever they did in the patch to Acrobat XI 11.0.03 solved the problem and the PDF looks good. It now only looks wrong when viewed in X which is what shipped with CS6.
I just tested with another ID document and it's exactly the same... color looks correct when opened in XI but not in X.
Adobe needs to get their act together and FIX WHAT IS BROKEN in X instead of forcing a $200 purchase to remedy the problem.
The profiles are in sync in ID and BOTH versions Acrobat Pro... North America General Purpose 2 (both are using U.S. Web Coated (SWOP) v2 for CMYK and sRGB for RGB).
There's a difference between syncing the Working CMYK spaces via Bridge and matching the Output Preview's Simulation profile—it's possible to be synced and have a different ID Assigned profile and Acrobat Output Simulation profile, syncing has no effect on those settings.
Are you getting different output numbers or is it just preview?
Well any local application change to the color settings is going to show up out of sync, but that aside I did check it...
Going into TOOLS > PRINT PRODUCTION. The Output Preview Simulation Profile on both versions of Acrobat match ID... both use U.S. Web Coated (SWOP) v2.
Numbers appear to be the same on the PDF when viewed in either X or XI.
Interestingly I did notice when entering the Print Production tool on XI that the PDF preview color shifted to match the incorrect version that shows up when viewing it normally in X. As soon as I back out of it, the color shifts back to what it looks like in InDesign or what I would get from a JPEG export out of ID.
So yes it may not be shifting numbers at all and is just a preview issue as mentioned... but it's still clearly messed up in X.
Well any local application change to the color settings is going to show up out of sync
All syncing does is match the application's Working CMYK and RGB settings, but the only case where a Working profile color manages a document is when the doc has no profile assignment. So if I sync to North American General my Working CMYK space is US SWOP, but if I open a document with US Sheetfed assigned, US Sheetfed manages the preview not US SWOP.
I'm not saying you aren't experiencing a bug, but you have to be sure of what profile assignments or simulation profiles are driving the preview and syncing doesn't do that. How you export (are you including profiles?, making a conversion?), and what device you are simulating in both programs can make syncing meaningless for existing document's previews.
I can't test X but with XI if you export a PDF/X-4 (where there's no conversion and all profiles are included), the preview with Output Preview closed shows RGB objects unchanged—same as ID with Overprint/Sep Preview Off.
When I open Output Preview the initial Simulation profile is the PDF/X-4 output intent which is the ID doc's assigned profile, in that case RGB objects preview in the output intent's CMYK space—same as ID with Overprint on.