I'm having a very weird problem with data being destroyed while writing/reading into Stata-MP on a slurm cluster.

After data cleaning, I am running isid, everything is fine, then I save the file as a dta. But when I immediately read in the exact same file, isid fails. One third of my 66M records are having their IDs values erased in the process. One of the ID variables is numeric and the other is a float (formatted as a date) Has anyone experienced this problem? Is this likely a server problem or is there something about the ID variables themselves that I could be unclear about?


Thank you. Explanatory code below. Unfortunately, my data are private so I can't share a sample.

Code:
  

. isid hhd_id date_DT  

.  
. * write  
. save $use_data/household_days, replace  
file /projects/project_name/data/use_data/household_days.dta saved  

.  
. use $use_data/household_days, clear  

.  
. isid hhd_id date_DT  
variables hhd_id and date_DT do not uniquely identify the observations r(459);