This is exactly the same on 3 identical internal hardware builds (2 with the same model case), 2 different types of cases. One with two USB 3.0 ports two different cases with only 1 front USB 2.0 and 1 front USB 3.0.
AND
It happens if you connect the motherboard USB 2.0 and a 3.0 to the front of case. Yes, weird, however I tested connecting a USB 2.0 and 3.0, the wireless mouse on either of them, then an external SSD Hard drive and the mouse quits. Same with a wired keyboard and the SSD drive. Back ports no problem.
Use both USB 3 ports with a "thumb drive" and the mouse quits too.
two of the cases are Epower Case EP-2002BB-500 Mid Tower with one USB 2.0 and one USB 3.0 front panel ports.
One is an In-Win EM013.TH350S3, mATX, with 350 watt power supply. 2 front USB 3.0 ports