I think that if there's an issue with the VR, it would most likely be in the PC that controls the headset rather than the headset itself overheating. There's 58 individual PCs in each train, all heating up the train, and that would likely cause issues depending on how well the PCs cope with running for long periods of time and overheating.
simple fix: water cooling.
It's annoying that they keep having technical issues that means the attraction has to be closed all day. It's probably annoying for them too, but nowhere near as annoying as it is for people who've traveled hours to ride it and not been able to.