I have a group of hosts that use the blacklist function in a monitor stanza in inputs.conf. Here is the referenced stanza:
[monitor:///usr/Interwoven/LiveSiteDisplayServices/runtime/tomcat/logs/*.log]
sourcetype = log4j
source = sfo-lsds-log
index = tnt13
blacklist = (http-client\.log$|globalsession\.log$|snapfish\.log$|livesite-runtime\.log$|catalina\.out$)
All of the logs in the blacklist do NOT get indexed to the referenced index (tnt13) in the stanza, but do get indexed to Main.
I have also tried the following, but the issue of events indexing to main persists:
[monitor:///usr/Interwoven/LiveSiteDisplayServices/runtime/tomcat/logs/]
sourcetype = log4j
source = sfo-lsds-log
index = tnt13
blacklist = http-client\.log$|globalsession\.log$|snapfish\.log$|livesite-runtime\.log$|catalina\.out$
Also of note, the source defined in the stanza does not appear to apply to the events as indexed in tnt13 or main.
I'd guess that you have another monitor stanza somewhere that's doing this.
Please run $splunkhome/bin/splunk cmd btool inputs list
and look through those results. If nothing pops out there, please run $splunkhome/bin/splunk cmd btool inputs list > myfile.txt
and then edit/read the resulting file and look through it.