Super-heavy trailer not possible (Combat Vehicles)

[RyuWanderfalke]

MegaMekLab 0.47.11
Stand alone
Windows 10
Java version 1.8.0_271

Description

Whenever I try to create a super-heavy combat vehicle trailer, the checkbox for trailer becomes uncheckable, no matter how often I click the box or in which order I try to do it (Vehicle type, super-heavy, trailer or trailer, super heavy, type etc.). Trailer for regular combat vehicles works fine and as intended, but super-heavy doesn't.