Low priority, probably, but should be simple to fix.
There's a class in Minecraft 18w43b which seems to provide number ranges, with integer and float subclasses. ("bc" obfuscated, you can probably find it by the "argument.range.empty" SimpleCommandExceptionType).
In that class, there's a method which outputs a JsonElement ("d"). Said method's logic can be modeled roughly as follows:
The second addProperty call seems to be setting "max" to this.min, whereas this.max is probably correct judging by context.
Essentially, a bit of code looking like
should probably look more like