One suspected bug in Writer is the inability to insert a useable tab between an autonumbered entry and its heading text in second and higher levels ToC entries. (The tabs in first-level ToC entries work fine.)
If a tab is inserted for the higher-level entries, it always is a right (quite undesired...) tab, thus making each second- or higher-level entry take up two lines per entry. Has anybody else experienced this LO feature? Formatting this tab in the dialog box does have a check box for selecting a right tab, but the box was not checked. My take is that the developers must have set all second- or higher-level tabs in the autonumbered entries to always be right tabs, by mistake.
There was another ToC bug, which I noticed earlier; however, I forgot its details because I went a different route.
Gary