This article provides clarification on the scenario when connecting a device using 10m link speed does not work in EX4400-48MP.
Connection not coming up as 10m speed.
EX4400-48MP >>> 10m speed <<< device
10m speed is not supported in EX4400-MP.
Per the below datasheet article, page 7, the EX4400 models that support 10m speed are:
EX4400-48P
EX4400-48T
EX4400-24P
EX4400-24T
ex4400-line-of-ethernet-switches-datasheet.pdf