Thread:Extension talk:SubPageList/Incompatible with SubPageList3?/reply

The idea is that you use only a single sub page list extension, not multiple. try only using SubPageList. That should work, and if it doesn't, this is a bug, which you should report. SubPageList being backwards compatible with SubPageList3 means that when using SubPageList3, and replacing it with SubPageList, the wikitext should still function the same.