I did some experiments with Pagelists and might have found a bug in the 0.73 Windows version. Since I was wrong the last time I thought I had found one, I'd appreciate it, if someone else could verify this.
Please open my test file and have a look at the .ncx file. Notice the Pagelist section at the end. Press CTRL+T to generate a new TOC and click OK.
On my machine the Pagelist sections gets deleted.
Since my test epub passed both epubcheck and FlightCrew I'm wondering if there is a problem with my Pagelist syntax that neither checker has caught or if Sigil cannot handle Pagelist sections in NCX files.