Why do you convert to a profile? No need for that. Indesign will handle the colors for you when you print. I have printed documents with 3 or 4 different source color spaces from Indesign a never converted to a profile.
For color matching in the printer driver, choose "None". If you choose a profile here, you have double profiling, which is what you suspected.
Ludwig
I should clarify, I set Adobe RGB as the document's color space, but am not having it do conversions—I opened the "Convert to Profile" dialog to show what the document's color space was set to, but I didn't click OK.
Unfortunately, I can't find anywhere in any of the driver settings to choose "None" for color matching. The only two options are ColorSync and Canon Color Matching (this panel is correctly disabled by apps like Photoshop and Lightroom, but for some reason, InDesign leaves it enabled). If I choose ColorSync, I have to pick an ICC profile; if I choose Canon Color Matching, there's nowhere in Canon's corresponding Color Options pane to force "None," which seems to have been an option on older driver versions.
For tonight, I was able to work around this problem by exporting a print-ready PDF with no color space conversion, and printing it using Preview with ColorSync for profiling. There must be
some way to do it from InDesign though, right?