Nothing saved to local storage for Flash-based game (Rusty Lake Hotel) (435120)

Compatibility Report

• Name of the game with compatibility issues: Rusty Lake Hotel
• Steam AppID of the game: 435120

System Information

• GPU: RX 580
• Driver/LLVM version: Mesa 18.3.1/7.0.1
• Kernel version: 4.20.3
• Link to full system information report as Gist: https://gist.github.com/hobb0001/d9dd819ef7923490dbeab8dfa2f7fd31
• Proton version: 3.16-4

I confirm:

• that I haven't found an existing compatibility report for this game.
• that I have checked whether there are updates for my system available.

steam-435120.log

Symptoms

The game doesn't want to save its progress. Since it's a Flash-based app, when the game first tries to save, Flash pops up a dialog box asking if it's ok for the app to use local storage. I select yes to allow up to 1MB of storage (the default). However, whenever I right-click on the game and look at local settings, I see that 0KB of local storage is being used. If I close the game and then start it again, it starts over from the very beginning.

Reproduction

• Start game
• Click "Continue", then "Play"
• Wait for introductory cut scene to finish
• Click on a shrimp cocktail (twice)
• Flash dialog appears asking if it's ok to use local storage
• Click "Allow"
• Right-click on the game and select "Settings..."
• Notice that the "Currently used" amount of local storage is "0KB"
• Close game
• Start game again
• Click "Continue", then "Play"
• Game starts over again from the very beginning

Start with the attached steam-435120.log and reproduce the Rusty Lake Hotel sequence described in the report, including allowing Flash local storage. Investigate the Proton compatibility behavior around the reported 0KB local-storage result; done means progress is retained after closing and restarting the game.