Yes, There was a thread here somewhere earlier this year about it, apparently the devs had reduced the effects of the trait in version 7.1.8 (good) but some people complained like crazy, so the devs have put it back to its old severe level in 8.1.0, grrrrr...
I stated my case at the time, I said that the trait should only be slapped on tanks that historically had a notorious reputation for breaking down, and that although tanks did break down in WW2, none had a really, really bad reputation for doing so.
I concluded by saying let the devs include the trait if they must, but please drastically reduce its effects, but I was overruled (sniffle).
PS- The trait also caught out another guy earlier this year, he posted something like- "What the hell?? My Shermans keep breaking down!! What kind of a crazy game is this??" We sympathised with him and pointed out that some of his Shermans had extra "sandbag armour" and the extra weight gave them the trait and made them prone to breakdown.
PS again- I'll make a list of all nationalities "Unreliable trait" vehs later and post it so we can avoid buying them..