While trying to place a wall by unlocking "graphic group lock" and "imply relationship lock" and then trying to break one layer of the wall (for example: insulation), the "break wall" command doesn't work from that moment even with the "locks" is switched back "ON".
This is a problem in the AECOsim 08.11.09.863 which has been already fixed in AECOsim 08.11.09.866 & CONNECT. Refer below to the video to check the workflow used to reproduce the solution in AECOsim Building Designer 08.11.09.866.
It is recommended that you should upgrade your system to AECOsim Building Designer 08.11.09.866 or CONNECT Edition for resolution of this issue.