Editing and save a group description, sometimes leads to the following error. Once the error happen the first time, it will happen again and again when editing this group description. 

Fatal error: Allowed memory size of 134217728 bytes exhausted (tried to allocate 57204057 bytes) in /var/www/virtual/xxxxxxxxxx.xx/htdocs/community/ow_core/database.php on line 707

After an browser refresh the changes are saved.

Latest Oxwall 1.7.2 is running

Do you have an idea what it is?