We now always do explodeRowspans before the first sort, to accomodate the new .sort() function. This has the unintended consequence that you basically cannot use rowspans at all anymore, since the JS code will always immediately fragment them back into individual cells right now.
This is a side effect of: https://gerrit.wikimedia.org/r/22562
Version: 1.21.x
Severity: critical