Yup, we've had the same experience. In our last two rental places we were completely ignored by the landlord for years, then they 'just happened to be in the area' and around 3-4 months later in each case, they told us they were putting the house on the market.
That's despite us asking them straight up whether they were going to sell (because we'd have put money aside for the next move), and the first landlord saying definitely not, the house was a family heirloom and he'd keep it rented out for ever. The next set also denied they'd be selling, then apparently when they turned around and gave us our two months notice it was 'a very hard decision'.
Why can't they just be honest? We're a family, we treated both houses well and always paid on time, what possible reason would they have to lie? It caused us no end of trouble because we trusted what they said so had to quickly find somewhere new and try to explain to our two DSs (who have ASD and don't take to change so easily) that we'd have to move again, in two months.
We are now at the point that we wouldn't trust any landlord as far as we could throw them (so it's a good thing we bought our next place!).
There needs to be better legislation to protect tenants, particularly families with young children. It's appalling in this country, very unstable and insecure.