I am not sure if you are referring to a Splunk for F5 Security, but, I am having some problems related to the extractions done by this app. I followed all the steps available on pdf which came with the app (that once named Creating-a-logging-profile-for-Splunk) and I noticed that when a fields is extracted, it is being extracted field_name=value, not just the field's value. It is being a problem to filter data because the website names into the combo boxes are being extracted the same way either. I wonder if there are additional configs to generate event logs which are not part of that available doc.
Someone having similar problems, I say, related with extractions done by this app?