The bug
When typing "/execute if block ~ ~ ~ water[level=", numbers 0-15 will be suggested. They are ordered by character rather than listing the numbers from least to greatest. See attached screenshot.
MC-125115
Command suggestions don't order numbers from least to greatest
Resolved
Fixed
0
Confirmed
command-syntax-help
Minecraft 18w06a, Minecraft 18w08b, Minecraft 18w11a, Minecraft 18w14a
Minecraft 18w19a
Retrieved
Still happen with the /bossbar command in 18w20c