ILM directories switched during report_timing - SOC81 USR3

I'm using the following script to time the toplevel timing.

===================================== 

restoreDesign opt.enc.dat  topmodule

specifyIlm -cell A -dir ./ilm_dir/A_ilm

specifyIlm -cell B  -dir ./ilm_dir/B_ilm

flattenIlm
report_timing

=====================================

When i look at the log file , i see that the tool creates and intermittent sdc file topmodule.ilm.sdc which has the fillowing

source sdc/topmodule.pt
set SOCE_SDC_PUSH_DOWN_IGNORED 1
current_instance
current_instance topmodule/A
source ./ilm_dir/B_ilm/B.core.sdc
current_instance
current_instance  topmodule/B
source ./ilm_dir/A_ilm/A.core.sdc
set SOCE_SDC_PUSH_DOWN_IGNORED 0

 I can see the switch in the sdc files when flattening the ilm.

I believe this is a issue and i'm not looking at the right timing, looking for some suggestion or comments  on the above behavior.

Appreciate your time.

Regards,

Vishnu