Based on my experience with FE International, if you're considering selling, I'd at least talk to them. They definitely earned my trust, and there's no obligation, but I bet they'd have some insights about red flags to look out for.
I have heard that this is increasingly happening as people are looking for bargains. i.e. If you're not shopping it around and they give you a big enough number to consider that's likely below what they'd pay in a bidding scenario, they get a good deal. Whereas otherwise, healthy SaaS businesses aren't going for cheap in general these days.
I'd certainly be cautious, though, especially if three came out of nowhere in a short period of time.