Current version sorting in BuildData.java is broken for patch numbers, as it does not convert to integer first before comparing the patch number. Only major and minor are properly compared as integers: https://hub.spigotmc.org/stash/projects/SPIGOT/repos/buildtools/browse/src/main/java/org/spigotmc/gui/data/BuildData.java#258-277

This results in 1.21.9 being shown first and compiled by default instead of the new 1.21.10.