It is the same, just not the indexed piece.
I have had many issues with logging in R80.30 and R80.40 and had to do a evstop and mdsstart to get it to resolve, but in your case it sounds like there is an issue with the indexer itself or there is a an issue in Solr, however rebooting the SMS and log server should resolve that.
Do keep in mind that your not directly connecting to the log server but to the SMS which is forwarding your request to the log server. so you should also do the evstop/cpstart on the SMS.
To restart Solr only:
cd /opt/CPrt-R81/scripts/
./stopSolr.sh;./startSolr.sh
Regards, Maarten