Turns out that installing Adobe CC can, after all, affect installations of non-CC software, unless you are very careful. Careful or not, it seem to have messed up my Nik plug-ins, as I thought it would (which don't work on CS6 anymore now that I've uninstalled CC from my Mac).
CC will update, more or less automatically, non-CC software to strip the (useful) functionalities that they inexplicably removed from newer versions of the software (i.e. the Output module from Bridge, easy exports from Bridge, etc.). I can't even remember having been prompted to update my non-CC Adobe Acrobat X licence, but it did so anyway and replaced it with a gutted version of Adobe Acrobat DC which works only half the time.
Haven't tried reinstalling and re-updating to the newest non-CC versions yet, but my little finger tells me that this might be an issue. Hoping it won't be, but my expectations are set very low at the moment.