Flying NRT-TPE-YYZ in paid J.
NRT-TPE leg was showing a 45 minute delay when I arrived at NRT; so I went to the gate for the previous NRT-TPE (183) flight and suggested they move me over in case the delay got any longer, putting my connection at risk. I was dealing first with the contract GA and then the BR lead

"Sorry, sir, business class is full on this flight"
Now I've flown enough to have a pretty good sense of what a full load for the Dreamliner looks like in the waiting area, and this was not it. There were maybe 100 people tops. I explained this.
"But sir, this plane hasn't started boarding yet. So many people haven't arrived. Business class is full on this flight"
I pointed out that the 183 was also delayed, boarding was supposed to have started 15 minutes ago.
This went back and forth for a few minutes, ultimately leading to:

"Sir you are right. Actually business class is not full on this flight. Shall we try to change your booking?"

I could have carried it further, but by this time I had already checked and seen that my own inbound was already airborne, and therefore the delay was not likely to get longer.
So I said "I don't want to continue this discussion further, because I don't want to lose my temper. But I think we can both agree that you have lied to me, repeatedly. It is not good practice to lie to customers"

I went off to the lounge.

Two hours later, I returned to the gate, the same one as the previous flight had left from. As I rounded the corner, I saw the BR team lead and two men in suits. The lead said something and then the two men started sprinting towards me. I momentarily worried that I was going to be in trouble for being argumentative. The two men turned out to be the station chief for BR at NRT and the supervisor for the contract staff. They both fell over themselves apologizing, and reassuring me that my connection was secure. I explained that I did not want to kick up a fuss, but I really thought it was very bad customer relations to lie to passengers. One of them tried to suggest that there had been a misunderstanding, but the other one, who knew full well that the conversation had been conducted in two different languages with the same result, shushed him.

Anyways, a very small problem - trying to switch flights to secure a connection - was now a very big problem. I'm guessing that both of the staff involved got into some trouble, despite my decision not to escalate. And EVA has one VERY dissatisfied and unhappy J class customer.