Thanks for reporting this issue. The latest version of CPLEX for AMPL switched to the new MP interface library, which currently has this bug in handling mipdisplay=2. The bug has been reported, and will be fixed in the next CPLEX for AMPL release.
To work around the problem, you can use outlev=1 to see output similar to that of mipdisplay=2. Alternatively, you can temporarily go back to using the older ASL interface library, by selecting “option solver cplexasl;”.