Whether any class action suit was ever actually attempted is irrelevant, it was talked about.
The relevant issue is how Kubota has treated B3350 owners, and continues to treat them. A case was cited earlier, B3350 owners shells out $4k because it was after the 5 year warranty period but before the date of the PSB (that few have heard of) and Kubota refused to reimburse the repair of a chronic issue. I doubt that after 7 years of a known chronic problem that Kubota issued the PSB just out of the goodness of their hearts.