Have estate agents seen property sales and chains collapsing in recent times?

I've seen a few stories cropping up in the media recently about lenders "pulling mortgage offers". I have a small issue with this, as it shouldn't happen except in a very specific set of circumstances. Since the Mortgage Market Review, any regulated mortgage contract (so this wouldn't include commercial loans or buy-to-let mortgages) is issued on a binding offer basis. This means the lender cannot simply withdraw its offer once made. There are, of course, some instances where they are allowed to if there are what are called material changes. For example, if the borrower's employment situation changes and they lose their job, if the property value is compromised, perhaps burnt down, or flooded, or if it became known the applicant purposely misled the lender on the application. One instance that is not a withdraw, but may be misrepresented as one, is if the offer reaches its expiry date and the applicant asks for an extension to it. Once the offer goes past its expiry date, it is no longer valid and so not binding. The lender could then refuse to extend, or only offer an extension on its current product range, i.e. a higher interest rate. If lenders are withdrawing offers outside of these material change rules I'd expect the FCA to be having an uncomfortable conversation with them very swifty.