Custom Steam Input controller mappings for Dual Sense controllers are broken with this new preview version

[geeksville]

Your system information

• Steam client version: alas I don't have the version # but behavior was identical between beta and stable versions of the client.
• SteamOS version: 3.6 preview (the build pushed to preview channel today 5/10/24)
• Opted into Steam client beta?: [Yes/No] tried both - behaviors same
• Opted into SteamOS beta?: [Yes/No] yes - this problem only appears on "Beta" or "Main", not stable.
• Have you checked for updates in Settings > System?: Yes

Please describe your issue in as much detail as possible:

I just switched from stable OS to preview OS ("beta" release). In general it was great (especially the better bluetooth performance).

But one serious problem made me revert back to stable: Any game when I'm using "custom" steam-input dualsensecontroller configs no longer seem to take effect. I seem to be getting only the 'no custom config' behavior. i.e. the menu button is mapped to the esc key, the dpad is regular dpad controller presses (rather than the translation to keyboard presses per my controller config).

If I look in the Steam big-picture UI it seems to think the custom control config is loaded but it isn't changing the actual control mappings.

The built-in steamdeck controller works fine. This problem seems to occur on the dualshock on either USB or bluetooth.

I tried a few different games - all with the same behavior. I tried both the "beta" and "stable" versions of the Steam client and the behavior was the same. The only thing that fixed this was to revert back to the SteamOS stable channel.

I saw https://github.com/ValveSoftware/SteamOS/issues/1500, but based on that description this sounds different.

Steps for reproducing this issue:

See above. I'm happy to add more context if helpful.