"Injected " is the key word.
Weights are ok as long as they are on the outside, but reading this would also exclude nitrogen.
I think this is just CYA statement due to lack of research/knowledge of these products.
I say lack of knowledge, because if they knew this was detrimental to their product or overall safety they would specifically point this out.
I believe you are absolutely correct. Not only is it a CYA type of statement, but it is similar to the various statements H-D has made over the years to try to weasel out of their obligations. For someone who has the time and resources to fight them (Dunflop or Harley), those statements are pretty meaningless in light of what Federal warranty law says. If Dunlop can
prove the beads caused your tire to delaminate and throw your butt in the weeds, you are out of luck and will have to go after the bead folks. However, if they can't prove it and you have a good lawyer, they will quickly settle and move on. The same would be true of some of the other statements in that Dunlop warranty that I posted and highlighted a short time back.
We've all seen various statements over the years that are legally unenforceable, but companies use them anyway to fend off the majority who won't fight. One of my favorites over the years was the one on the repair order at a car or bike dealership where by signing the form you agree they aren't responsible for your vehicle while you leave it in their control. Total BS, yet I still see it on some repair order forms. I've always wanted to see how that statement would protect them when they dropped a car off a lift (which I did see on one occassion btw), or they left the car out in the lot with the key in it and it got stolen, or the tech used it to ride cross town and get lunch and totalled it.
What I'm trying to say in this meandering post is, be aware of the warranty and the exclusions going in, but don't let them BS you or bully you into not doing what you want. Just think, if we all had believed the BS Harley used to put out about synthetic oil we would all still be like Hoist, riding around with old decomposed dinosaurs in the crankcase.

Jerry