Users will need to comment out or remove the following lines in their top.qsf file:
# base revision compile SDC constraints only
set_global_assignment -name SDC_FILE base.sdc
set_global_assignment -disable -name SDC_FILE top.sdc
set_global_assignment -disable -name SDC_FILE top_post.sdc
It will be required to do another import compile after changing the QSF file
aoc --board .cl
This problem is scheduled to be fixed in a future release of the Intel FPGA SDK for OpenCL.