Lantana camara is a declared weed in Australia. The pink or pink/red varieties are the ones that have spread most into pastureland and the seeds and leaves are regarded as toxic to stock.
I've a purple and a yellow cultivar, the latter is lovely, a terrific flowerer in a rockery where I prune it back really hard a couple of times a year and it blooms for months. I've never found seed on it. the purple is more a trailer and suckers a bit. I actually like the smell of the leaves of those two, quite aromatic but that's the problem I guess for some.
Even the sale of the cultivars is prohibited in Australia which is a bit of a pity if you are in suburbia and want a very drought-hardy plant.
But I sympathise with people on the land for whom the weedy variety it is a constant and expensive struggle to eradicate, as it will resist slashing, burning, poisoning.
Australia, in the wisdom (?) of its bio people, introduced a lantana bug, Aconophora compressa, some years ago. There weren't really enough bugs to do the lantana to death before the extreme heat of summer got to them, they preferred to hang around suburban gardens and feast on other verbenacea like native "Fiddlewood". Now the bugs are trying to be eradicated. Just a little bit of trivia

My understanding is that the purple and yellow ones are actually a different species. They're said to be only propagated by cuttings, not seed. I have the yellow, but the purple has disappeared. Previously had a small bushy upright one which I believed wouldn't seed. I did find a plant growing well away from the garden where there was no irrigation. It was surviving our dry season. Pulled the garden plant and the 'weed' one out but do find the occasional additional plant around. Obviously someone else has the plants. But the taller, rambling ones have become a real menace in parts of the world.