I know it is a bit late but for those that have the same problem and land on this page (like myself):
The problem setting is "autosummaryperc" in limits.conf
auto_summary_perc = <integer>
* The maximum number of concurrent searches to be allocated for auto
summarization, as a percentage of the concurrent searches that the scheduler
* Auto summary searches include:
* Searches which generate the data for the Report Acceleration feature.
* Searches which generate the data for Data Model acceleration.
* Note: user scheduled searches take precedence over auto summary searches.
* Defaults to 50.