Here is the picture to show what's happening.

Notice after 61...
It's set to sort by "name (numeric)", because "name" does number orders all weird like sorting this sequence:
1 2 3 4 5 6 7 8 9 10 11 12
as:
1 10 11 12 2 3 4 5 6 7 8 9
Moderators: helmut, XnTriq, xnview