Hanging mod command

[David Engeset <davidke@whidbey.net>]

   I am running OpenLDAP 2.2.26.  I have recently ran into a problem 
when I try to add a new attribute to an entry that has top and 
groupOfNames as its only objectClasses, it will hang when trying to run 
ldap_mod_add.  In the ldap log file it shows the line that it is 
performing a mod:
slapd[19807]: conn=78 op=1 MOD attr=member
but it will not finish and post the next line that shows it completed.  
The strange part about this problem is once I have killed slapd and 
recovered the database I can do the exact same operation and it works 
fine.  I then I leave it alone and the next morning try again it will 
hang on the same operation.  But I can do other ldap_mod_adds on other 
entries of different objectClasses and they do not hang and then do the 
group mod and it hangs.
   Any ideas of what is happening and/or causing this would be greatly 
appreciated.
Thank you,

--
David