(forwarding request from huwiki village pump)
Category pages auto-generate list section headers based on the initial letters of the category members. Sometimes the column break is just after such a header:

A                   * B1
* A1                * B2
* A2                C
* A3                * C1
B                   * C2

Standard typography convention is to not leave a single line of a paragraph before the column break; the same should apply even stronger for list headers.