First, There is no lawsuits launched, some law firm is trying to gather information to see if there is even a case.
There are so many people here arguing the wrong things. It doesn't matter if OnePlus didn't tell you anything in relation to a lawsuit. The technical aspects pretty much doesn't matter.
This is how the law works in the USA (most states) and this lawfirm is a US firm, so we'll assume generic US law (IANAL, this is not legal advice, lawyers please correct me):
In most states, in order to bring a fraud case forward (this is what this lawsuit will be, basically saying that the company misrepresented or implied facts), the claimant needs the following to establish standing. What is standing?
1. Injury in fact: you suffered some kind of loss (physical, economic, etc), that
2. Causation: the defendants (OnePlus in this case) caused, and
3. Redressable: the specific losses suffered can be redressed in some way, usually with $$$.
Let's dive into each one:
1. You, and the class, need to PROVE an INJURY IN FACT. This does not mean you think you got a slower processor than advertised, or the performance of the device did not match expectations. This is specific things like (just for example) Chrome loaded a page so slowly that you lost a client and contract worth $5000. Things like that where you need to prove the induced fraud caused a real loss. Feelings don't count, and hypothetical events don't count. This is pretty much gonna be $0 for everyone, this case is pretty much DOA.
2. The class need to prove that the damages suffered by class members were directly caused by OnePlus. This isn't hard to do, the device is maufactured, marketed, and sold by OnePlus in the US.
3. Redressablility: The class need to show that some way exists to make the class members whole. This is literally a toggle they are implementing in A12, barring any other possible damages in 1
If this case gets filed, I don't see it surviving the first motion to dismiss before anything even happens. It's not worth the filing fees unless someone shows up with some actual, real $$$$$ losses due to thermal throttle (and PROVE it).