https://wccftech.com/latest-samsung-galaxy-s9-s9-update-reportedly-restored-call-recording-capability-in-some-units/

The Samsung Galaxy S9 and S9+ received the May security patch update only a few days ago. Along with the updated security patch, the update also restored call recording functionalities of the device, which were previously broken. The change was first noticed by a Reddit user, later to be confirmed by other users. The build number of the update for the S9 and S9+ is G960FXXU1BRE5 and G965FXXU1BRE3 respectively and has rolled out to several countries such as Russia, Switzerland, Spain, Romania, Netherlands, and in the UK, with more countries to be added soon. All the devices that can record calls are Exynos-based and restricted to the European region, so far.

Ideally, the call recording should have been disabled in regions that don’t allow it and vice versa. Samsung thought it would be better the axe the feature altogether, presumably to avoid potential lawsuits. However, the feature is appearing in devices in the United Kingdom on devices running this latest patch. The UK is a two-party consent region, where recording a call without both the parties being aware of it is considered a wire-tap. To combat unauthorized recording of phone calls, Android P might even play a tone when it detects that a call recorder is active in the background, though we haven’t seen it in action on any of the Android P developer previews so far.