I'm getting the same error as this old issue: https://github.com/FAForever/downlords-faf-client/issues/1312
Clicking on any leaderboard replay launches FAF, and this popup appears:
Unable to load game replay from C:\ProgramData\FAForever\cache\temp.scfareplay [ Ok ]
Looking at the game log file, it doesn't seem like there's any particular error of note: game_16625204.log
I'm not totally sure what's going wrong.